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Word_Problems_With_Coins/162721: 1. A piggy bank has 250 pieces of assorted coins, 3/4 of which are 10.00 peso coins. The other coins are 5.00 peso, 1.00 peso and .25 cents coins, in the proportion of 3:4:3.Since the owner finds out that .25 cents coins can easili comes out from the piggy hole he decided to extract all these .25 coins. What is the total amount saved?
1 solutions

Answer 119962 by ankor@dixie-net.com(15660) About Me  on 2008-10-18 10:26:00 (Show Source):
You can put this solution on YOUR website!
3%2F4 of 250 is not an integer (187.5). What gives here?


Numbers_Word_Problems/162687: This question is from textbook
Hilary has three times as much money as Paul. Jeff has $4 less than Hilary and $5 more than Paul. How much money does each have?
1 solutions

Answer 119929 by ankor@dixie-net.com(15660) About Me  on 2008-10-17 21:22:58 (Show Source):
You can put this solution on YOUR website!
Hilary has three times as much money as Paul.
H = 3P
:
Jeff has $4 less than Hilary"
J = H - 4
Substitute 3P for H
J = 3P - 4
:
"and $5 more than Paul"
J = P + 5
:
rearrange these two equations
J - 3P = -4
J - P = 5
---------------subtraction eliminates J, find P
-2P = -9
P = %28-9%29%2F%28-2%29
P = $4.50
then
H = 3(4.5); from the 1st equation
H = $13.50
and
J = P + 5
J = 4.50 + 5
J = $9.50
:
Confirm this with the equation J = H - 4
J = 13.50 - 4
J = $9.50
:
Hopefully this made sense to you. Let me know.


Complex_Numbers/162523: Write the expression as a complex number in standard form:
six minus i square roots of 2 divided by six plus i square roots of 2
1 solutions

Answer 119912 by ankor@dixie-net.com(15660) About Me  on 2008-10-17 18:07:03 (Show Source):
You can put this solution on YOUR website!
six minus i square roots of 2 divided by six plus i square roots of 2
:
%286+-+i%2Asqrt%282%29%29%2F%286+%2B+i%2Asqrt%282%29%29
Multiply by the conjugate of the denominator over itself
%286+-+i%2Asqrt%282%29%29%2F%286+%2B+i%2Asqrt%282%29%29 * %286+-+i%2Asqrt%282%29%29%2F%286+-+i%2Asqrt%282%29%29 = %2836+-+12i%2Asqrt%282%29+%2B+i%5E2%282%29%29%2F%2836+-+i%5E2%282%29%29 = %2836+-+12i%2Asqrt%282%29+%2B+%28-1%29%282%29%29%2F%2836+-+%28-1%29%282%29%29 = %2836+-+12i%2Asqrt%282%29+-+2%29%2F%2836+%2B+2%29 = %2834+-+12i%2Asqrt%282%29%29%2F38
reduce the fraction:
%2817+-+6i%2Asqrt%282%29%29%2F19


Travel_Word_Problems/162653: This question is from textbook beginning and intermediate algebra
a plane can fly 400 miles downwind in the same amount of time as it can travel 320 miles upwind. If the plane can fly at 360 miles per hour in still air. Find the speed of the wind. I need to revise my exam
1 solutions

Answer 119906 by ankor@dixie-net.com(15660) About Me  on 2008-10-17 16:34:18 (Show Source):
You can put this solution on YOUR website!
plane can fly 400 miles downwind in the same amount of time as it can travel 320 miles upwind. If the plane can fly at 360 miles per hour in still air. Find the speed of the wind.
:
Let x = speed of the wind
then
(360-x) speed against the wind
and
(360+x) speed with the wind
:
It says the times are equal for flying 400 mi and 320 mi. Write a time equation
time = distance%2Fspeed
:
Time with the wind = time against the wind
400%2F%28%28360%2Bx%29%29 = 320%2F%28%28360-x%29%29
Cross multiply
320(360+x) = 400(360-x)
:
115200 + 320x = 144000 - 400x
:
320x + 400x = 144000 - 114200
:
720x = 28800
x = 28800%2F720
x = 40 mph is the wind
:
:
Check the solution, find out if the times are equal:
Using the wind, the speed with 400, speed against 320
400/400 = 1 hr
320/320 = 1 hr


Problems-with-consecutive-odd-even-integers/162685: One integer is 6 less than another integer. The product of the lesser integer and -7 is 42 more than the greater integer. What are the integers?
1 solutions

Answer 119905 by ankor@dixie-net.com(15660) About Me  on 2008-10-17 16:07:17 (Show Source):
You can put this solution on YOUR website!
One integer is 6 less than another integer. The product of the lesser integer and -7 is 42 more than the greater integer. What are the integers?
:
I don't think there is a solution to this, but let's proceed like there is:
:
Let x = larger integer
Let y = lesser integer
:
Write an equation for each statement:
"One integer is 6 less than another integer."
y = x - 6
:
" The product of the lesser integer and -7 is 42 more than the greater integer."
y * -7 = 42 + x
we can write it:
-7y = x + 42
:
Substitute (x-6) for y (from the 1st statement)
-7(x-6) = x + 42
-7x + 42 = x + 42
You can see we are in real trouble here
-7x = x; not possible


What are the integers? there aren't any


Human-and-algebraic-language/162645: A homeowner wants to fence a rectangular garden using 120ft of fencing. The side of the garage will be used as one side of the rectangle. Find the dimenstions for which the area is a maximum.
1 solutions

Answer 119904 by ankor@dixie-net.com(15660) About Me  on 2008-10-17 15:53:40 (Show Source):
You can put this solution on YOUR website!
A homeowner wants to fence a rectangular garden using 120ft of fencing. The side of the garage will be used as one side of the rectangle. Find the dimensions for which the area is a maximum.
:
The perimeter equation with one side being the garage:
L + 2W = 120
or
L = (120 - 2W)
;
Area = W * L
Substitute (120-2W) for L and you have:
A = W(120-2W)
A = 120W - 2W^2
This can be arranged as a quadratic equation
-2W^2 + 120W = 0
:
To find the maximum, find the axis symmetry using x = %28-b%29%2F%282%2Aa%29
In this equation:
W = %28-120%29%2F%282%2A-2%29
W = %28-120%29%2F%28-4%29
W = +30 ft is the width for max area
Find L
L = 120 - 2(30)
L = 60 ft is the length
;
Find the max area, substitute 30 for W in the equation
A = -2(30^2) + 120(30)
A = -1800 = 3600
A = +1800 sq/ft is the maximum area
:
:
Check solution by finding the area with the dimensions:
60 * 30 = 1800 sq/ft


Travel_Word_Problems/162664: During the first part of a trip, a canoeist travels 69 miles at a certain speed. The canoeist travels 2 miles on the second part of the trip at a speed 5 mph slower. The total time for the trip is 3 hrs. What was the speed on each part of the trip?
1 solutions

Answer 119893 by ankor@dixie-net.com(15660) About Me  on 2008-10-17 13:33:59 (Show Source):
You can put this solution on YOUR website!
During the first part of a trip, a canoeist travels 69 miles at a certain speed. The canoeist travels 2 miles on the second part of the trip at a speed 5 mph slower. The total time for the trip is 3 hrs. What was the speed on each part of the trip?
;
Canoing that far in 3 hrs is a fantasy, but anyway:
:
Let s = speed on the 69 miles
then
(s-5) = speed on the last to miles of the trip
:
Write a time equation: Time = dist/speed
:
69 mi time + 2 mi time = 3 hrs
69%2Fs + 2%2F%28%28s-5%29%29 = 3
:
Multiply equation by s(s-5), results:
69(s-5) + 2s = 3s(s-5)
69s - 345 + 2s = 3s^2 - 15s
71s - 345 = 3s^2 - 15s
0 = 3s^2 - 15s = 71s + 345
A quadratic equation:
3s^2 - 86s + 345 = 0
Use the quadratic formula to solve this
The solution that makes sense is s ~ 23.84 mph for the 1st 69mi
and
23.84 - 5 = 18.84 mph for the last two mi
:
:
Check solution by finding the times at each speed
69/23.84 = 2.89 hrs
2/18.84 = .106 hr
----------------
total time 2.996 ~ 3 hrs
:
I suspect there may be a typo in this as written here, but the method should
help you.


Numeric_Fractions/162655: Can someone help me with this problem. I know that it is simple but I have drawn a blank. And, can the steps be broken down so that I can understand other problems that may be similiar in the future.

5 and 3/4-2 and 2/5
1 solutions

Answer 119888 by ankor@dixie-net.com(15660) About Me  on 2008-10-17 12:43:14 (Show Source):
You can put this solution on YOUR website!
53%2F4 - 22%2F5
:
Convert both fractions to improper fractions. Multiply the whole number times the
denominator and add the numerator
23%2F4 - 12%2F5
:
They need to have a common denominator, 20 is a multiple of both denominators
20/4 = 5 and 20/5 = 4, so we have
5*23%2F20 - 4*12%2F20
which is
115%2F20 - 48%2F20 = 67%2F20
:
Convert this to a mixed number, divide 20 into 67, the remainder is the fraction
37%2F20


Linear-equations/162649: hi,
Can u solve this system of linear equation?
The question is:
x-y 4
___ = _
x+y 5
Its x-y divided by x+y which is equal to 4 divided by 5
I need the answer today.
Thank u
1 solutions

Answer 119876 by ankor@dixie-net.com(15660) About Me  on 2008-10-17 11:09:26 (Show Source):
You can put this solution on YOUR website!
Assume the problems is:
%28%28x-y%29%29%2F%28%28x%2By%29%29 = 4%2F5
:
From this we can say:
x - y = 4
x + y = 5
---------------adding eliminates y, find x
2x = 9
x = 9%2F2
x = 4.5
:
Find y using x + y = 5
4.5 + y = 5
y = 5 - 4.5
y = .5
:
Check solution in original equation:
%28%284.5-.5%29%29%2F%28%284.5%2B.5%29%29 = 4%2F5
4%2F5 = 4%2F5


Rational-functions/162579: edy is about ti take a test that contains short-answer question worth 4 points each and word problems worth 7 points each. edy must do at least 5 short-answer questions, but time rrestricts doing more than 10. she must do at least 3 word problems, but time restricts doing more than 10. edy can do no more than 18 questions in total. how many of each type of question must edy do in order to maximize her score? what is this maximum score?
1 solutions

Answer 119870 by ankor@dixie-net.com(15660) About Me  on 2008-10-17 09:48:59 (Show Source):
You can put this solution on YOUR website!
Edy is about to take a test that contains short-answer question worth 4 points
each, and word problems worth 7 points each. Edy must do at least 5 short-answer
questions, but time restricts doing more than 10. She must do at least 3 word
problems, but time restricts doing more than 10. Edy can do no more than 18
questions in total. How many of each type of question must Edy do in order to
maximize her score? What is this maximum score?
:
Let x = no. of short answer problems
Let y = no. of word problems
:
x => 5; must do at least 5
x =< 10 can do no more than 10
:
y => 3; must to at least 3
y =< 10; can do no more than 10
:
x + y =< 18; Can do no more than 18 total
:
Score = 4x + 7y
It does not say to graph. Try this. Start with min x and max y
4(5) + 7(10) = 90
:
That's 15 problems, we can do 18, therefore, add 3 more short ans problems
4(8) + 7(10) = 110 is the max score
;
That seems to satisfy all constraints.
She should do 8 short ans problems, and 10 word problems for score of 110


Complex_Numbers/162611: (2+3i)^2 could you please explain step by step
please help soon!
1 solutions

Answer 119826 by ankor@dixie-net.com(15660) About Me  on 2008-10-16 21:41:51 (Show Source):
You can put this solution on YOUR website!
(2+3i)^2 could you please explain step by step
:
Assume you want to FOIL (2+3i)(2+3i)
Step by step
F: mult first two term 2 * 2 = 4
0: mult outer terms: 2 * 3i = 6i
I: mult inner terms: 3i * 2 = 6i
L: mult last terms: 3i * 3i = 9i^2
:
So we have:
4 + 6i + 6i + 9i^2
:
Add like terms
4 + 12i + 9i^2
;
Remember that i^2 = -1 so you have:
4 + 12i + 9(-1)
4 + 12i - 9
:
4 - 9 + 12i
:
which is:
-5 + 12i


Polynomials-and-rational-expressions/162590: one moreee the biggest problem i have is word problems i hate them and i get frustrated heres one i'm really struggling with.
a board is cut into two pieces. one piece is to be three times as long as the other. if the board is 4.2m long, what will the length of the longer piece be?
i have to have a let statement i tried putting..
let x represent 1 piece
let x+3 reprsent the other piece
so i put the equation as..
2x+3=4.2
but the number is so small i find it hard to believe it correct! can you show me what im doing wrong?
1 solutions

Answer 119825 by ankor@dixie-net.com(15660) About Me  on 2008-10-16 21:03:31 (Show Source):
You can put this solution on YOUR website!
a board is cut into two pieces. one piece is to be three times as long as the
other. if the board is 4.2m long, what will the length of the longer piece be?
:
Let's do it this way:
:
Let x = the smaller piece
It said,"one piece is to be three times as long as the other."
therefore:
3x = the long piece
:
small piece + longer piece = 4.2 meters
x + 3x = 4.2
:
4x = 4.2
:
Divide both sides by 4
x = 4.2%2F4
x = 1.05 m is the smaller piece
:
They ask for the length of the longer piece:
3 * 1.05 = 3.15 m is the longer piece
:
:
Check to see if this is true, add the two pieces
1.05 + 3.15 = 4.2
:
Did this help?


Linear-systems/162558: a basketball team sells tickets that cost $10 $20 or VIP seats, $30. The team has sold 492 tickets over all. It has sold 177 more $20 tickets than $10 tickets. The total sales are $8580. How Many tickets of each kind have been sold?
1 solutions

Answer 119824 by ankor@dixie-net.com(15660) About Me  on 2008-10-16 20:07:49 (Show Source):
You can put this solution on YOUR website!
A basketball team sells tickets that cost $10 $20 or VIP seats, $30.
The no. of three types of tickets = x, y, z
;
The team has sold 492 tickets over all.
x + y + z = 492
:
It has sold 177 more $20 tickets than $10 tickets.
y = x + 177
:
The total sales are $8580.
10x + 20y + 30z = 8580
:
How Many tickets of each kind have been sold?
:
Replace (x+177) for y in the 1st and 3rd equations
x + (177+x) + z = 492
2x + z = 492 - 177
2x + z = 315
and
10x + 20(x+177) + 30z = 8580
10x + 20x + 3540 + 30z = 8580
30x + 30z = 8580 - 3540
30x + 30z = 5040
Simplify, divide equation by 30
x + z = 168
:
Using these two equations for elimination
2x + z = 315
x + z = 168
---------------subtracting eliminates z
x = 147 ea $10 tickets sold
:
y = 147 + 177
y = 324 ea $20 tickets sold
;
Find z using the 1st equation
147 + 324 + z = 492
471 + z = 492
z = 492 - 471
z = 21 ea $30 tickets sold
:
Check solution in the $$ equation
10(147) + 20(324) + 30(21) =
1470 + 6480 + 630 = 8580; confirms our solutions


Graphs/162486: write thev equation of a line in the form Ax+By=C throgh the point (-5,-3)and perpendicular to the line y= - 2over3x+6
1 solutions

Answer 119802 by ankor@dixie-net.com(15660) About Me  on 2008-10-16 19:01:40 (Show Source):
You can put this solution on YOUR website!
write the equation of a line in the form Ax+By=C through the point (-5,-3)and perpendicular to the line y= -(2/3)x+6
:
Determine the slope m2, the relationship of perpendicular lines: m1*m2=-1
Let m1 = -2%2F3
-2%2F3*m2 = -1
m2 = -1*-3%2F2
m2 = 3%2F2
:
Use the point/slope formula
y - (-3) = 3%2F2(x - (-5)
y + 3 = 3%2F2(x +5)
y + 3 = 3%2F2x + 15%2F2
y = 3%2F2x + 15%2F2 - 3
y = 3%2F2x + 15%2F2 - 6%2F2
y = 3%2F2x + 9%2F2
Get rid of the denominators multiply equation by 2
2y = 3x + 9
arrange in the required format
-3x + 2y = 9


Linear-equations/162443: A hotdog stand can purchase hotdogs for $.35 each and buns for $.20 each. It has fixed costs of $50. Each hotdog is sold for $1.
write a linear equation for both cost and revenue.
Graph both cost and revenue.
Estimate the break-even point.

1 solutions

Answer 119796 by ankor@dixie-net.com(15660) About Me  on 2008-10-16 18:18:23 (Show Source):
You can put this solution on YOUR website!
A hot-dog stand can purchase hot-dogs for $.35 each and buns for $.20 each.
It has fixed costs of $50. Each hot-dog is sold for $1.
:
write a linear equation for both cost and revenue.
Let x = no. sold; each cost .35+ .20 = .55
Cost = .55x + 50
Rev = 1x
:
Graph both cost and revenue.
+graph%28+300%2C+200%2C+-40%2C+150%2C+-40%2C+150%2C+x%2C+.55x%2B50%29+
Cost: green
Rev: purple
:
Estimate the break-even point. How about 110 hot dogs sold at $110


Surface-area/162480: How many gallons of water are in a well that is 36 inches in diameter and 20 feet deep?
1 solutions

Answer 119760 by ankor@dixie-net.com(15660) About Me  on 2008-10-16 15:50:22 (Show Source):
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How many gallons of water are in a well that is 36 inches in diameter and 20 feet deep?
:
Change 36" diameter to 3 feet, radius will = 1.5 ft
:
Find the volume of a cylinder
V = pi%2Ar%5E2%2Ah
where: r=1.5, h= 20
V = pi%2A1.5%5E2%2A20
V = 141.37 cu/ft
:
1 cu/ft = 7.481 gallons
:
141.37 * 7.481 = 1057.6 gallons


Polynomials-and-rational-expressions/162414: Please help to solve
Simplify and evaluate:
(2^x^5y^-3z^4/4^0x^-2y^-8z^5)^3
I don't think I am coming up with the correct answer.
12x^3 z^9/y^11
1 solutions

Answer 119758 by ankor@dixie-net.com(15660) About Me  on 2008-10-16 15:41:45 (Show Source):
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I assume you mean 2x%5E5 not 2%5Ex%5E5
%28%28%282x%5E5y%5E-3z%5E4%29%29%2F%28%284%5E0x%5E-2y%5E-8z%5E5%29%29%29%5E3
4^0 = 1 so we can ignore that
%28%28%282x%5E5y%5E-3z%5E4%29%29%2F%28%28x%5E-2y%5E-8z%5E5%29%29%29%5E3
Combine the exponents of like terms in a way to make them positive
= %28%282x%5E7y%5E5%29%2F%28z%5E1%29%29%5E3
Multiply all the exponents by 3
%282%5E3x%5E21y%5E15%29%2F%28z%5E3%29%29 = %288x%5E21y%5E15%29%2F%28z%5E3%29%29


Geometry_Word_Problems/162431: A and B working together can do a job in 20/3 hours. A became ill after 3 hours of working with B and B finished the job, continuing the work alone in 33/4 more hours. How long would it take each working alone to do the job????
1 solutions

Answer 119750 by ankor@dixie-net.com(15660) About Me  on 2008-10-16 14:53:33 (Show Source):
You can put this solution on YOUR website!
A and B working together can do a job in 20/3 hours. A becames ill after 3 hours
of working with B and B finished the job, continuing the work alone in 33/4 more
hours. How long would it take each working alone to do the job????
:
Let a = A's time working alone
Let b = B's time working alone
Let the completed job = 1
:
Equation 1, for the statement,"A and B working together can do a job in 20/3 hours"
%2820%2F3%29%2Fa + %2820%2F3%29%2Fb = 1
Which is:
20%2F%283a%29 + 20%2F%283b%29 = 1; (we invert the dividing fraction and multiply)
:
Equation 2 when A gets sick:
B works 3 hr + 33/4 hr = 45/4; hrs total for B
:
3%2Fa + 45%2F%284b%29 = 1
Multiply the 1st fraction by 3/3 to have same denominator as the 1st equation
9%2F%283a%29 + 45%2F%284b%29 = 1
;
Try to use elimination here with these two equations:
9%2F%283a%29 + 45%2F%284b%29 = 1
20%2F%283a%29 + 20%2F%283b%29 = 1
:
Multiply the 1st equation by 20, and the 2nd equation by 9, results:
180%2F%283a%29 + 900%2F%284b%29 = 20
180%2F%283a%29 + 180%2F%283b%29 = 9
---------------------------------------subtraction eliminates a, leaving:
900%2F%284b%29 - 180%2F%283%29 = 11
225%2Fb - 60%2Fb = 11; reduced the fractions
165%2Fb = 11
b = 165%2F11
b = 15 hrs by himself
:
Find a using eq: 20%2F%283a%29 + 20%2F%283b%29 = 1;
20%2F%283a%29 + 20%2F%283%2A15%29 = 1;
20%2F%283a%29 + 20%2F45 = 1;
20%2F%283a%29 + 4%2F9 = 1; reduced the fraction
20%2F%283a%29 = 1 - 4%2F9%29
20%2F%283a%29 = 5%2F9%29
Cross multiply
5(3a) = 20*9
15a = 180
a = 180%2F15
a = 12 hrs by himself
:
:
Check solution using eq;9%2F%283a%29 + 45%2F%284b%29 = 1
9%2F%2836%29 + 45%2F%2860%29 = 1
1%2F4 + 3%2F4%29 = 1; confirms the solutions to this horrible problem!


Mixture_Word_Problems/162391: A container is partly filled with 12 liters of whole milk containing 4% butterfat. How much 1% milk must be added to get a mixture that is 2% butterfat?
1 solutions

Answer 119686 by ankor@dixie-net.com(15660) About Me  on 2008-10-15 21:49:13 (Show Source):
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A container is partly filled with 12 liters of whole milk containing 4% butterfat.
How much 1% milk must be added to get a mixture that is 2% butterfat?
:
Let x = amt of 1% milk
then
(x+12) = resulting amt
:
Write an "amt of butterfat" equation
;
.01x + .04(12) = .02(x+12)
:
.01x + .48 = .02x + .24
:
.48 - .24 = .02x - .01x
:
.24 = .01x
x = .24%2F.01
x = 24 liters of 1% milk required
:
:
Check solution in the original equation:
.01(24) + .04(12) = .02(24+12)
.24 + .48 = .02(36
.72 = .72; confirms our solution


Human-and-algebraic-language/162366: dianne has six steel balls of equal mass. if she puts five of them in one pan of a beam balance and one ball and a 100 g mass in the other pan, the pans balance each other. what is the mass of each steel ball?
1 solutions

Answer 119685 by ankor@dixie-net.com(15660) About Me  on 2008-10-15 21:37:25 (Show Source):
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Dianne has six steel balls of equal mass. If she puts five of them in one pan
of a beam balance and one ball and a 100 g mass in the other pan,
the pans balance each other. What is the mass of each steel ball?
:
Let x = mass of 1 steel ball
:
5x = x + 100
:
5x - x = 100
:
4x = 100
x = 100%2F4
x = 25 gr
:
:
Check solution in original equation
5(25) = 25 + 100


Reduction-of-unit-multipliers/162390: 1qt/min = (?)gal/week
1 solutions

Answer 119682 by ankor@dixie-net.com(15660) About Me  on 2008-10-15 21:32:09 (Show Source):
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1qt/min = (?)gal/week
:
We find the no. of min in 1 week, then change quarts to gallons
%28%2860+%2A+24+%2A+7%29%29%2F4 2520 gal/week


Linear-systems/162404: I would love it if you would tell me I'm doing this right, however, if I am not please help me to see what I am doing wrong.
Solve the linear equation by graphing
2x-y=5 3x+y=5
y=-2x+5 y=3x-5
my answer: 2,1
1 solutions

Answer 119681 by ankor@dixie-net.com(15660) About Me  on 2008-10-15 21:27:45 (Show Source):
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Solve the linear equation by graphing
2x-y=5 3x+y=5
y=-2x+5 y=3x-5
:
the 1st equation:
2x - y = 5
-y = -2x + 5
we must have the coefficient of y to be positive 1, multiply the equation by -1
y = 2x - 5
:
:
The 2nd equation
3x + y = 5
y = -3x + 5
:
you must change the signs when you move a term from one side to the other.
:
Graphing these:
+graph%28+300%2C+200%2C+-2%2C+5%2C+-6%2C+6%2C+2x-5%2C+-3x%2B5%29+
You can see the solution is: 2,-1


Money_Word_Problems/162396: In the period of a year, an investor lost twice as much as he gained. if he originally had $10,000 and now has $8,000. What amount did he gain and what did he lose?
1 solutions

Answer 119680 by ankor@dixie-net.com(15660) About Me  on 2008-10-15 21:16:58 (Show Source):
You can put this solution on YOUR website!
In the period of a year, an investor lost twice as much as he gained.
If he originally had $10,000 and now has $8,000.
What amount did he gain and what did he lose?
:
Let x = amt he gained
then
2x = amt he lost
:
$10000 + gained - lost = $8000
;
10000 + x - 2x = 8000
:
10000 - x = 8000
:
-x = 8000 - 10000
:
-x = -2000
:
x = 2000 he gained
and
2x = 4000 he lost


Travel_Word_Problems/162351: Mr. Turner has a motorboat that can travel 14 mph in still water. He wishes to take a trip on a river whose current flows at the rate of 2 mph. If he has 7 hours at his disposal, how many hours should he spend on the first part of his trip going downstream before returning upstream to his starting point?
1 solutions

Answer 119662 by ankor@dixie-net.com(15660) About Me  on 2008-10-15 18:51:41 (Show Source):
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Mr. Turner has a motorboat that can travel 14 mph in still water.
He wishes to take a trip on a river whose current flows at the rate of 2 mph.
If he has 7 hours at his disposal, how many hours should he spend on the first
part of his trip going downstream before returning upstream to his starting point?
:
Let t = time going down-stream
then
(7-t) = time going up-stream
:
14 + 2 = 16 mph; boat speed down-stream
14 - 2 - 12 mph; boat speed up-stream
:
Distance both ways are the same, write a dist equation: dist = speed * time
:
Dist down = dist up
16t = 12(7-t)
:
16t = 84 - 12t
:
16t + 12t = 84
:
28t = 84
t = 84%2F28
t = 3 hrs he can travel down-stream, before he has 4 hrs to return
:
:
confirm solution by finding the distances down and back:
16*3 = 48 mi
12*4 = 48 mi


Polynomials-and-rational-expressions/162053: CAN SOMEONE HELP ME WITH THIS PROBLEM
In the formula A = I^ekt, A is the amount of radioactive material remaining from an initial amount I at a given time t and k is a negative constant determined by the nature of the material. An artifact is discovered at a certain site. If it has 53% of the carbon-14 it originally contained, what is the approximate age of the artifact? (carbon-14 decays at the rate of 0.0125% annually.) (Round to the nearest year.)
1 solutions

Answer 119651 by ankor@dixie-net.com(15660) About Me  on 2008-10-15 17:55:20 (Show Source):
You can put this solution on YOUR website!
In the formula A = I^ekt, A is the amount of radioactive material remaining from an initial amount I at a given time t and k is a negative constant determined by the nature of the material. An artifact is discovered at a certain site. If it has 53% of the carbon-14 it originally contained, what is the approximate age of the artifact? (carbon-14 decays at the rate of 0.0125% annually.) (Round to the nearest year.)
:
I think the formula should be A = I*e^(-kt)
In this problem:
Assume I = 1
A = .53
Decimal value for .0125% = .000125
:
e^(-.000125t) = .53
;
-.000125t*ln(e) = ln(.53)
;
-.000125t = -.6834878; (the ln of e is 1)
t = %28-.6834878%29%2F%28-.000125%29
t = 5,079 years


Travel_Word_Problems/162019: ROSE DROVE HER CAR FROM HER HOME TO THE PROVINCE AND BACK,A TOTAL DISTANCE OF 120KM.HER AVERAGE SPEED RETURNING WAS 3KPH SLOWER THAN HER AVERAGE SPEED GOING TO THE PROVINCE.IF HER TOTAL DRIVING TIME WAS 9 HOURS ,WHAT WAS HER AVERAGE SPEED IN GOING TO THE PROVINCE?
1 solutions

Answer 119635 by ankor@dixie-net.com(15660) About Me  on 2008-10-15 16:43:08 (Show Source):
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ROSE DROVE HER CAR FROM HER HOME TO THE PROVINCE AND BACK, A TOTAL DISTANCE OF
120KM. HER AVERAGE SPEED RETURNING, WAS 3KPH SLOWER THAN HER AVERAGE SPEED
GOING, TO THE PROVINCE. IF HER TOTAL DRIVING TIME WAS 9 HOURS,
WHAT WAS HER AVERAGE SPEED IN GOING TO THE PROVINCE?
:
From the given information we can assume that one way; 120/2 = 60 km
:
Let s = her speed going
and
(s-3) = her speed returning
:
Write a time equation: Time = dist%2Fspeed
Go time + return time = 9 hrs
60%2Fs + 60%2F%28%28s-3%29%29 = 9
:
Eliminate the denominators, multiply equation by s(s-3), results:
60(s-3) + 60s = 9(s(s-3))
;
60s - 180 + 60s = 9(s^2 - 3s)
:
120s - 180 = 9s^2 - 27s
:
0 = 9s^2 - 27s - 120s + 180
A quadratic equation:
9s^2 - 147s + 180 = 0
This can be factored to
(3s - 45)(3s - 4) = 0
Two solutions
3s = 4
s = 4%2F3
and
3s = 45
s = 15 km/h this seems to be the most reasonable
:
Speed going: 15 km/h; and speed returning 12 km/h
:
Check in original equation
60/15 + 60/12 =
4 + 5 = 9 hrs


Travel_Word_Problems/162311: Alexander and Judy are 32 miles apart on a calm lake paddling toward each other. Alexander paddles at 4 miles per hour, while judy paddles at 7 miles per hour. How long will it take them to meet?
1 solutions

Answer 119626 by ankor@dixie-net.com(15660) About Me  on 2008-10-15 16:11:56 (Show Source):
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Alexander and Judy are 32 miles apart on a calm lake paddling toward each other.
Alexander paddles at 4 miles per hour, while judy paddles at 7 miles per hour.
How long will it take them to meet?
:
Let t = their paddling time
:
When they meet, their travel distances will add up to 32: Dist = speed * time
:
4t + 7t = 32
;
11t = 32
t = 32/11
t = 2.91 hrs or about 2 hrs 54.6 minutes
:
:
Check the solution by finding the distance of each:
2.91*4 = 11.64
2.91*7 = 20.37
-------------
total = 32.01 ~ 32


Finance/162310: CAN SOMEONE PLEASE HELP ME WITH THIS PROBLEM:
Suppose the amount of a radioactive element remaining in a sample of 100 milligrams after x years can be described by A(x) = 100e^-0.01657x. How much is remaining after 257 years? Round to the nearest hundredth of a milligram.
a. 0.01 milli
b. 1.42 milli
c. 425.85 milli
d. 7070.31 milli
1 solutions

Answer 119622 by ankor@dixie-net.com(15660) About Me  on 2008-10-15 15:55:28 (Show Source):
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Suppose the amount of a radioactive element remaining in a sample of 100
milligrams after x years can be described by A(x) = 100e^-0.01657x.
How much is remaining after 257 years?
Round to the nearest hundredth of a milligram.
:
A(x) = 100%2Ae%5E%28-0.01657x%29
:
Substitute 257 for x;
A(x) = 100%2Ae%5E%28-0.01657%2A257%29
:
A(x) = 100%2Ae%5E-4.25849
:
on a good calc find: e%5E-4.25849
A(x) = 100 * .01414
:
A(x) = 1.41 milligrams


Miscellaneous_Word_Problems/162301: Marcie can walk 8 miles in the same time as Frank walks 6 miles. If Marcie walks 1 mile per hour faster than Frank, then how fast does each person walk?
1 solutions

Answer 119620 by ankor@dixie-net.com(15660) About Me  on 2008-10-15 15:29:27 (Show Source):
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Marcie can walk 8 miles in the same time as Frank walks 6 miles. If Marcie walks 1 mile per hour faster than Frank, then how fast does each person walk?
:
Let s = F's walking speed
then
(s+1) = M's walking speed
:
It says the times are equal; write a time equation: Time = dist%2Fspeed
M's time = F's time
8%2F%28%28s%2B1%29%29 = 6%2Fs
Cross multiply
8s = 6(s+1)
8s = 6s + 6
8s - 6s = 6
2s = 6
s = 6%2F2
s = 3 mph is F's speed
and
4 mph is M's speed
:
;
Check solutions by ensuring the times are equal:
8/4 = 2hr
6/3 = 2hr


Equations/162302: Solve the equation
1/3 x^2 + 1/2x = 1/3
1 solutions

Answer 119618 by ankor@dixie-net.com(15660) About Me  on 2008-10-15 15:18:34 (Show Source):
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Solve the equation
%281%2F3%29x%5E2 + %281%2F2%29x = 1%2F3
:
We can get rid of those annoying denominator by multiplying by 6:
6*%281%2F3%29x%5E2 + 6*%281%2F2%29x = 6*1%2F3
Cancel out the denominators and you have:
2x^2 + 3x = 2
:
Arrange as a quadratic equation:
2x^2 + 3x - 2 = 0
:
This factors to:
(2x - 1)(x + 2) = 0
:
2x = +1
x = 1%2F2
and
x = -2
:
Check x=-2 in original equation
%281%2F3%29%28-2%5E2%29 + %281%2F2%29%28-2%29 = 1%2F3
%281%2F3%29%284%29 + %28%28-2%29%2F2%29 = 1%2F3
4%2F3 - 1 = 1%2F3
:
I give you the honor of checking the x = 1/2 solution


Miscellaneous_Word_Problems/162163: Hans paid $1.50 each for programs to the game. He sold all but 20 of them for $3 each and made a profit of $15. How many programs did he buy?
1 solutions

Answer 119617 by ankor@dixie-net.com(15660) About Me  on 2008-10-15 14:26:14 (Show Source):
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Hans paid $1.50 each for programs to the game. He sold all but 20 of them for $3 each and made a profit of $15. How many programs did he buy?
:
Let x = no. of programs he bought
Then
(x-20) = no of programs he sold
:
$amt sold - $amt paid = profit
3(x-20) - 1.5x = 15
:
3x - 60 - 1.5x = 15
:
3x - 1.5x = 15 + 60
:
1.5x = 75
x = 75%2F1.5
x = 50 programs originally bought
:
:
Check: 3(30) - 1.5(50) = 15