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josmiceli answered: 9642 problems
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Trigonometry-basics/251514: can you graph
2sinx-cos2
1 solutions

Answer 183270 by josmiceli(9645) About Me  on 2009-12-19 17:09:15 (Show Source):


Miscellaneous_Word_Problems/251479: How many revolutions per minute does a wheel make if its angular velocity is
120 pi radians per hour?
a) 1 rpm b) 2pi rpm c) 1/60 rpm d) 3600 rpm e) 7200 rpm
1 solutions

Answer 183182 by josmiceli(9645) About Me  on 2009-12-19 10:51:32 (Show Source):
You can put this solution on YOUR website!
120%2Api radians/hr x (1 hr/60 min) = 2%2Api radians/min
2%2Api radians/min x (1 revolution/2%2Apiradians) = 1 rpm
The answer is a)


Miscellaneous_Word_Problems/251387: The bacteria E Coli are found in the human bladder. Suppose 2,000 bacteria are present at time t = 0. Then, t minutes later the number of bacteria present can be approximated by N(t) = 2000(3)t/12.


How many bacteria will be present after 40 minutes?
How long will it take before there are 100,000 bacteria present?
1 solutions

Answer 183084 by josmiceli(9645) About Me  on 2009-12-18 18:14:37 (Show Source):
You can put this solution on YOUR website!
N%28t%29+=+2000%2A3%5E%28t%2F12%29
given:
t+=+40 min
N%2840%29+=+2000%2A3%5E%2840%2F12%29
N%2840%29+=+2000%2A3%5E%2810%2F3%29
N%2840%29+=+2000%2A38.94
N%2840%29+=+77881
-----------------
given:
N%28t%29+=+100000
100000+=2000%2A3%5E%28t%2F12%29
50+=+3%5E%28t%2F12%29
Take the log of both sides
log%2850%29+=+log%283%5E%28t%2F12%29%29
1.69897+=+%28t%2F12%29%2Alog%283%29
1.69897+=+.47712%2A%28t%2F12%29
t%2F12+=+1.69897%2F.47712
t%2F12+=+3.56088
t+=+42.73 min


absolute-value/248846: -|x+56|=-65
1 solutions

Answer 181322 by josmiceli(9645) About Me  on 2009-12-11 21:46:31 (Show Source):
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-+abs%28x+%2B+56%29+=+-65
Multiply both sides by -1
abs%28x+%2B+56%29+=+65
x+=+9
x+=+-121


Quadratic_Equations/248836: bill & jose's discount cinema sold adults' tickets for $4.10 each and children's tickets for $2.70 each. last tuesday, a total of $331.30 was collected from 89 movie watchers. how many of each type of ticket were sold? (let x represent the number of adults' tickets and y represent the number of children's tickets.)
4. solve by applying the quadratic formula. show your work. 3x2 - 2x + 3 = 0.
1 solutions

Answer 181319 by josmiceli(9645) About Me  on 2009-12-11 21:36:34 (Show Source):
You can put this solution on YOUR website!
Let x = number of adult tickets sold
Let y = number of children's tickets sold
given:
410x+%2B+270y+=+33130 (in cents)
(1) 41x+%2B+27y+=+3313
(2) x+%2B+y+=+89
Multiply both sides of (2) by 27
and subtract from (1)
(1) 41x+%2B+27y+=+3313
(2) -27x+-+27y+=+-2403
14x+=+910
x+=+65
and, since
x+%2B+y+=+89
65+%2B+y+=+89
y+=+89+-+65
y+=+24
65 adult tickets and 24 children's tickets were sold
check:
(1) 41x+%2B+27y+=+3313
41%2A65+%2B+27%2A24+=+3313
2665+%2B+648+=+3313
3313+=+3313
OK


Expressions-with-variables/248641: "solve the problem" A closed box with a square base is required to have a volume of 10 cubic feet. Express the amount of material used to make such a box as a function of the length x of a side of the square base?
I tried to start with f(x)=10/x+x

thanks for any help
1 solutions

Answer 181188 by josmiceli(9645) About Me  on 2009-12-11 10:03:08 (Show Source):
You can put this solution on YOUR website!
Let h = height
Let x = side of square base
The volume is
V+=+x%5E2%2Ah
given:
10+=+x%5E2%2Ah
h+=+10%2Fx%5E2
The area of the closed box is:
f%28x%29+=+x%5E2+%2B+x%5E2+%2B+4%2Ax%2A%2810%2Fx%5E2%29
f%28x%29+=+2x%5E2+%2B+40%2Fx m2 answer


Quadratic_Equations/248644: The so called golden rectangle is said to be extremely pleasing visually and was used often by ancient Greek and Roman Architects. The length of a golden rectangle is approx. 1.6 times the width. Find the dimensions of a golden rectangle if its area is 9000m^2.
1 solutions

Answer 181176 by josmiceli(9645) About Me  on 2009-12-11 09:21:36 (Show Source):
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Let l = length
Let w = width
l%2Aw+=+9000 m2
given:
l+=+1.6w
%281.6w%29%2Aw+=+9000
1.6w%5E2+=+9000
w%5E2+=+5625
w+=+75
l+=+1.6w
l+=+1.6%2A75
l+=+120
The length is 120 m and the width is 75 m


Coordinate-system/248642: identifiy the slope of the given by the equation y-5=-2(x+5). THEN identify one point on the line.

1 solutions

Answer 181175 by josmiceli(9645) About Me  on 2009-12-11 09:16:48 (Show Source):
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First, get the equation into the form y+=+mx+%2B+b
y+-+5+=+-2%2A%28x+%2B+5%29
Add 5 to both sides
y+=+-2%2A%28x+%2B+5%29+%2B+5
y+=+-2x+-+10+%2B+5
y+=+-2x+-5
m+=+-2
The slope is -2
To find a point on the line just randomly pick any value for either
x or y
I'll say x+=+-15
y+=+-2x+-+5
y+=+-2%2A%28-15%29+-+5
y+=+30+-+5
y+=+25
Therefore, (-15,25) is a point on the line


logarithm/248628: Please help really stumped! Approximately one-third of all glass bottles distributed will be recycled each year. A beverage company distributes 310,000 bottles. The number still in use after t years is given by the function
N(t)=310,000(1/2)^t
After how many years will 60,000 bottles still be in use?
.
1 solutions

Answer 181171 by josmiceli(9645) About Me  on 2009-12-11 08:56:34 (Show Source):
You can put this solution on YOUR website!
The 1st part of the problem seems to say that 2/3 of the bottles
are still in use after 1 year, but the formula seems to say that
1/2 of the bottles are still in use after 1 year. I'm stumped, too


Miscellaneous_Word_Problems/248629: One maid can clean the house three times faster than another. Working together they can clean the entire house in 3 hours. How long would it take the faster maid cleaning alone?
1 solutions

Answer 181169 by josmiceli(9645) About Me  on 2009-12-11 08:36:40 (Show Source):
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Faster maid's rate of working + slower maids rate = rate working together
Let x = slower maids rate of working in (1 house cleaned)/(time to clean it)
then, Faster maid's rate = 3x
x+%2B+3x+=+1%2F3 (note: 1/3 is: (1 house/(3 hours))
3x+%2B+9x+=+1
12x+=+1
x+=+1%2F12
The slower maid can clean 1 house in 12 hours
The faster maid's rate is:
3x+=+3%2A%281%2F12%29+=+3%2F12
3%2F12+=+1%2F4
The faster maid can clean the house in 4 hours


Proportions/248635: A 3-men crew can do a certain job in 3 weeks and 2 days, if we are to hire 4 men crew instead, with the same rate as the first crew, how long would it take the 4-men crew to do the same job? Note: a week contains 6 working days and a work day is 8 hours.
1 solutions

Answer 181168 by josmiceli(9645) About Me  on 2009-12-11 08:26:58 (Show Source):
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A good question to ask is: If 3 men can do a job in a certain time,
how long will it take 1 man to do the job working alone?
given:
A 3-men crew can do a certain job in 3 weeks and 2 days
Using logic, it will take 1 man 3 times as long to do the same job
So, 1 man will take 9 weeks and 6 days to do the job
(9 weeks) x (6 working days/week) = 54 working days
54 days + 6 days = 60 days
(60 days) x (8 hours/day) = 480 hours
-----------------------------
Using logic again, It will take 4 men 1/4 of the time that it
takes 1 man to do the job
%281%2F4%29%2A480+=+120 hrs
(120 hrs) x (1 day/8 hrs) = 15 days
(15 days) x (1 week/6 days) = 2.5 weeks
(.5 weeks) x (6 days/week) = 3 days
It will take the 4 men 2 weeks and 3 days to do the job


Travel_Word_Problems/248633: Trent can deliver his newspapers in 30 minutes. It takes Lois 20 minutes to do the same route. How long would it take them to deliver the newspapers if they work together?
1 solutions

Answer 181167 by josmiceli(9645) About Me  on 2009-12-11 08:05:28 (Show Source):
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Trent's rate of delivering papers plus
Lois's rate of delivering papers equals
their rate working together.
In words:
(1 route)/(Trent's time) + (1 route)/(Lois's time) = (1 route)/(time working together)
1%2F30+%2B+1%2F20+=+1%2Fx
Multiply both sides by 60x
2x+%2B+3x+=+60
5x+=+60
x+=+12 minutes


Miscellaneous_Word_Problems/248364: If each boy purchases a patty and each girl purchases a bun, they would spend a total of one cent more than if each boy purchased a bun and each girl purchased a patty. We know that the number of boys is greater than the number of girls. What is the difference between the number of boys and the number of girls?
1 solutions

Answer 181023 by josmiceli(9645) About Me  on 2009-12-10 18:01:19 (Show Source):
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Let x = price of a bun in cents
Let y = price of a patty in cents
Let b = number of boys
Let g = number of girls
given:
b%2Ay+%2B+g%2Ax+=+b%2Ax+%2B+g%2Ay+%2B+1
subtract b%2Ax from both sides
b%2Ay+-+b%2Ax+%2B+g%2Ax+=+g%2Ay+%2B+1
Subtract g%2Ax from both sides
b%2Ay+-+b%2Ax+=+g%2Ay+-+g%2Ax+%2B+1
b%2A%28y+-+x%29+=+g%2A%28y+-+x%29+%2B+1
Divide both sides by y+-+x
b+=+g+%2B+1%2F%28y+-+x%29
b+-+g+=+1%2F%28y+-+x%29 answer


Word_Problems_With_Coins/248373: Mike has 15 coins. One third of them are dimes; the rest are nickels. How much money does Mike have? How would I solve this problem?
1 solutions

Answer 181011 by josmiceli(9645) About Me  on 2009-12-10 17:39:39 (Show Source):
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Let d = number of dimes he has
Let n = number of nickels he has
given:
d+%2B+n+=+15
d+=+%281%2F3%29%2A15
d+=+5
5+%2B+n+=+15
n+=+10
He has 5 dimes and 10 nickels
10d+%2B+5n = total
5%2A10++%2B+10%2A5+=+100
He has 100 cents, or $1


Polygons/248366: A 50-gon is a polygon with 50 sides. How could you find the sum of the angles in a 50-gon? What is the answer?
1 solutions

Answer 181002 by josmiceli(9645) About Me  on 2009-12-10 17:31:34 (Show Source):
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First, draw lines from each vertex to some common point inside the figure
If I start going part way around the polygon, and look only at the triangles
formed by the lines I just drew, I add up the interior angles of each triangle.
If the angle in the center of the 1st triangle is A, it's angles add ip to
180+-+A, and for the 2nd triangle,
180+-+B, and for the 3rd triangle,
180+-+C
There are exactly 50 of these triangles, so adding up all their angles, I get
50%2A180 - (A + B + C + D + . . .)
I will run out of letters, but there must be 50 of them. Since they go
completely around the interior point of the polygon, they add up to 360 degress, so
50%2A180+-+360 degrees is the answer
50%2A180+-+360+=+9000+-+360
9000+-+360+=+8640 degrees


Polynomials-and-rational-expressions/246714: Factor the polynomial.
x^3-y^9
1 solutions

Answer 180291 by josmiceli(9645) About Me  on 2009-12-07 21:27:31 (Show Source):
You can put this solution on YOUR website!
x%5E3+-+y%5E9
%28x%5E1.5+%2B+y%5E4.5%29%2A%28x%5E1.5+-+y%5E4.5%29
I'd like to check this
Suppose x+=+16 and y+=+9
x%5E3+-+y%5E9
16%5E3+-+9%5E9
By my calculator:
4096+-+387420489+=+-387416393
And my solution:
%28x%5E1.5+%2B+y%5E4.5%29%2A%28x%5E1.5+-+y%5E4.5%29
%2816%5E1.5+%2B+9%5E4.5%29%2A%2816%5E1.5+-+9%5E4.5%29
%284%5E3+%2B+3%5E9%29%2A%284%5E3+-+3%5E9%29
%2864+%2B+19683%29%2A%2864+-+19683%29
19747%2A%28-19619%29+=+-387416393
OK


Mixture_Word_Problems/246889: A standard deck of 52 playing cards consists of four different suits
and 13 cards of different ranks in each suit. Four cards will be drawn at
random without replacement from this deck. The probability that the
four cards will be all the same suit is k times the probability that they
will be all the same rank. What is the value of k?
1 solutions

Answer 180222 by josmiceli(9645) About Me  on 2009-12-07 18:15:10 (Show Source):
You can put this solution on YOUR website!
If I want P1(4 cards same suit), I don't care what
the 1st card is, so I'll call P1(1st card) = 1,
which means I'm certain to get any one of the cards.
Now I have that card, and it is a certain suit, say
clubs. There are 12 clubs left, so my chances of getting
another club is
P2+=+12%2F51
Now there are 11 clubs left
P3+=+11%2F50, and
P4+=+10%2F49
P%5Bss%5D+=+P1%2AP2%2AP3%2AP4
P%5Bss%5D+=+1%2A12%2F51%2A11%2F50%2A10%2F49
-----------------------------------
There are 13 groups of 4 cards which are the same rank
I don't care what the 1st card is
P1+=+1
I've got the 1st card. Say it is a 9
P2+=+3%2F51 is P2(another 9)
P3+=+2%2F50 is P3(another 9)
P4+=+1%2F49 is P4(another 9)
P%5Bsr%5D+=+1%2A3%2F51%2A2%2F50%2A1%2F49
--------------------------------------
given:
P%5Bss%5D+=+k%2AP%5Bsr%5D
k+=+P%5Bss%5D%2FP%5Bsr%5D
k+=+%2812%2F51%2A11%2F50%2A10%2F49%29%2F%283%2F51%2A2%2F50%2A1%2F49%29
Multiply right side by %2851%2A50%2A49%29%2F%2851%2A50%2A49%29
k+=+%2812%2A11%2A10%29%2F%283%2A2%2A1%29
k+=+220


Word_Problems_With_Coins/246221: Paula can have pennies, nickels, dimes, and quarters in her purse. The average value of coins in her purse is 20 cents. If she adds one more quarter to her purse, the average value of all the coins will be 21 cents. How many nickels does she have in her purse?
1 solutions

Answer 179869 by josmiceli(9645) About Me  on 2009-12-05 23:20:33 (Show Source):
You can put this solution on YOUR website!
Let a = amount of money in her purse
Let n = number of coins in her purse
given:
a%2Fn+=+20
%28a+%2B+25%29%2F%28n+%2B+1%29+=+21
---------------------
a+=+20n
%2820n+%2B+25%29%2F%28n+%2B+1%29+=+21
20n+%2B+25+=+21%2A%28n+%2B+1%29
20n+%2B+25+=+21n+%2B+21
n+=+4
a+=+20%2A4
a+=+80
The only 4 coins that give me 80 cents is 3 quarters and 1 nickel
she has 1 nickel
check:
%2820n+%2B+25%29%2F%28n+%2B+1%29+=+21
%2820%2A4+%2B+25%29%2F5+=+21
105%2F5+=+21
105+=+105
OK


Quadratic_Equations/246206: a quadratic function is defined by f(x)= 3x^2+4x-2. A linear function is defined by g(x)=mx-5. What value(s) of the slope owuld make it a tangeant to the prabola

The answer to the problem is m=-2, and m=10
1 solutions

Answer 179850 by josmiceli(9645) About Me  on 2009-12-05 20:59:31 (Show Source):
You can put this solution on YOUR website!
Is this question part of a calculus course? The answer
is easiest with calculus.
f%28x%29+=+3x%5E2+%2B+4x+-+2
fprime%28x%29+=+6x+%2B+4
g%28x%29+=mx+-+5
gprime%28x%29+=+m
I want to know all solutions x%5B1%5D%2Cy%5B1%5D
where
fprime%28x%5B1%5D%29+=+gprime%28x%5B1%5D%29
6x+%2B+4+=+m
Also, x%5B1%5D%2Cy%5B1%5D is a solution for
f%28x%29+=+g%28x%29
3x%5E2+%2B+4x+-+2+=+mx+-+5
3x%5E2+%2B+4x+-+2+=+%286x+%2B+4%29%2Ax+-+5
3x%5E2+%2B+4x+-+2+=+6x%5E2+%2B+4x+-+5
3x%5E2+=+3
x%5E2+=+1
x+=+1
x+=+-1
and
fprime%281%29+=+6%2A1+%2B+4
fprime%281%29+=+10
gprime%281%29+=+m
since
fprime%281%29+=+gprime%281%29
m+=+10
fprime%28-1%29+=+6%2A%28-1%29+%2B+4
fprime%28-1%29+=+-2
gprime%28-1%29+=+m
m+=+-2
I'll do a plot of the quadratic and 2 lines:
+graph%28+600%2C+600%2C+-4%2C+4%2C+-7%2C+8%2C+3x%5E2+%2B+4x+-+2%2C+10x+-+5%2C-2x+-+5+%29+


Pythagorean-theorem/242965: The sides of a right triangle have lengths x – y, x, x + y, where x>y>0.
Find the ratio of x : y.

1 solutions

Answer 178009 by josmiceli(9645) About Me  on 2009-11-27 11:57:36 (Show Source):
You can put this solution on YOUR website!
x%5E2+%2B+%28x-y%29%5E2+=+%28x+%2B+y%29%5E2
x%5E2+%2B+x%5E2+-+2xy+%2B+y%5E2+=+x%5E2+%2B+2xy+%2B+y%5E2
2x%5E2+-+4xy+%2B+y%5E2+=+x%5E2+%2B+y%5E2
x%5E2+-+4xy+%2B+y%5E2+=+y%5E2
x%5E2+=+4xy
x+=+4y
x%2Fy+=+4
check nanswer:
x%5E2+%2B+%28x-y%29%5E2+=+%28x+%2B+y%29%5E2
%284y%29%5E2+%2B+%284y-y%29%5E2+=+%284y+%2B+y%29%5E2
+16y%5E2+%2B+9y%5E2+=+25y%5E2
25y%5E2+=+25y%5E2
OK


Equations/242990: Please help me solve this equation: 3x^2 - 2x = 12.
1 solutions

Answer 178007 by josmiceli(9645) About Me  on 2009-11-27 11:36:37 (Show Source):
You can put this solution on YOUR website!
3x%5E2+-+2x+=+12
Subtract 12 from both sides
3x%5E2+-+2x+-+12+=+0
Now this is in the general form
ax%5E2+%2B+bx+%2B+c+=+0
Now apply the quadratic formula
x+=+%28-b+%2B-+sqrt%28+b%5E2-4%2Aa%2Ac+%29%29%2F%282%2Aa%29+
where
a+=+3
b+=+-2
c+=+-12
x+=+%28-%28-2%29+%2B-+sqrt%28+%28-2%29%5E2-4%2A3%2A%28-12%29+%29%29%2F%282%2A3%29+
x+=+%28+2+%2B-+sqrt%28+4+%2B+144+%29%29%2F+6+
x+=+%28+2+%2B-+2%2Asqrt%28+37+%29%29%2F+6+
x+=+%28+1+%2B-+sqrt%28+37+%29%29%2F+3+
The answers are:
x+=+%281+%2B+sqrt%2837%29%29%2F3
and
x+=+%281+-+sqrt%2837%29%29%2F3
It's a difficult process, but you can plug
these answers (one at a time) back into the
original equation and see if they work


Travel_Word_Problems/242993: My car gets 25 mpg for in-town driving, and 40 mpg on the highway. If I used 51 gallons on a recent 1800 mile trip, how many miles were highway miles?
1 solutions

Answer 178004 by josmiceli(9645) About Me  on 2009-11-27 11:23:42 (Show Source):
You can put this solution on YOUR website!
Let h = highway miles driven
Let t = in-town miles driven
given:
(1) h+%2B+t+=+1800 mi
(2) h%2F40+%2B+t%2F25+=+51 gallons
---------------------
Note that (miles)/(miles/gallon) = (miles) x (gallons/mile) = gallons
I have 2 equations and 2 unknowns, so it's solvable
(2) h%2F40+%2B+t%2F25+=+51
Multiply both sides by 200
(2) 5h+%2B+8t+=+10200
Now multiply both sides of (1) by 5
and subtract (1) from (2)
5h+%2B+8t+=+10200
-5h+-+5t+=+-9000
3t+=+1200
t+=+400
Plug this back into (1)
h+%2B+t+=+1800
h+%2B+400+=+1800
h+=+1400
1400 miles were highway miles
check answer:
(2) h%2F40+%2B+t%2F25+=+51
1400%2F40+%2B+400%2F25+=+51
35+%2B+16+=+51
51+=+51
OK


Systems-of-equations/242018: It says to solve the problem by using the substitution method, elimination method or graphing method.
2(x-y)=3+x, x=3y+4
1 solutions

Answer 177189 by josmiceli(9645) About Me  on 2009-11-23 12:52:18 (Show Source):
You can put this solution on YOUR website!
I'll graph them
2%2A%28x-y%29+=+3+%2B+x
2x+-+2y+=+3+%2B+x
-2y+=+-2x+%2B+x+%2B+3
-2y+=+1x+%2B+3
y+=+-%281%2F2%29%2Ax+-+3%2F2
and
x+=+3y+%2B+4
3y+=+x+-+4
y+=+%281%2F3%29%2Ax+-+4%2F3


Polynomials-and-rational-expressions/242008: Hi
I submitted these problems but no one has help me, can someone please help me I been out of school for 15 years and I am talking college algebra, here are the problems.

1. factor into product of 2 binomials:
5x(6x-5) -2(6x-5)
This is what I got
5*x(6*x-5) – 12*x+10

2. factor completely, if the polynomial is a prime, state this:
49y^2-49w^2
This is what I got for the answer:
49*y^-49*w^2

1 solutions

Answer 177182 by josmiceli(9645) About Me  on 2009-11-23 12:00:59 (Show Source):
You can put this solution on YOUR website!
Note that 6x+-+5 is a factor in both terms
5x%2A%286x+-+5%29-+2%2A%286x+-+5%29
%286x+-+5%29%2A%285x+-+2%29 answer
----------------------
49y%5E2+-+49w%5E2
%287y+%2B+7w%29%2A%287y+-+7w%29
And I can factor out the 7's
7%2A%28y+%2B+w%29%2A7%2A%28y+-+w%29
49%2A%28y+%2B+w%29%2A%28y+-+w%29 answer


Trigonometry-basics/241987: Can you help me convert 36 degrees to a radian?
1 solutions

Answer 177171 by josmiceli(9645) About Me  on 2009-11-23 10:41:47 (Show Source):
You can put this solution on YOUR website!
There are 2%2Api radians in a circle
If you are given an angle in degrees,
(number of degrees) x (2%2Api radians/360 degrees)
is your conversion formula
36 degrees x 2%2Api%2F360 radians/degree = %2836%2F360%29%2A2%2Api
%281%2F10%29%2A2%2Api
pi%2F5 radians answer
There should be 10 pi%2F5 radians in a circle, and there are:
10%2A%28pi%2F5%29+=+2%2Api
OK


Miscellaneous_Word_Problems/241985: bill has 10 coins which are quarters and dimes if his quarters were dimes and his dimes were quarters the total is 30 cents more how many quarters does he has?
1 solutions

Answer 177167 by josmiceli(9645) About Me  on 2009-11-23 10:32:12 (Show Source):
You can put this solution on YOUR website!
Let d = number of dimes he has
Let q = number of quarters he has
given:
(1)d+%2B+q+=+10
(2) 10d+%2B+25q+%2B+30+=+10q+%2B+25d
---------------------------------------
Notice that on the right side, I make the quarters
worth 10 each and dimes worth 25 each
From (1):
(1) q+=+10+-+d
And, substituting:
(2) 10d+%2B+25%2A%2810+-+d%29+%2B+30+=+10%2A%2810+-+d%29+%2B+25d
10d+%2B+250+-+25d+%2B+30+=+100+-+10d+%2B+25d
-15d+%2B+280+=+15d+%2B+100
30d+=+180
d+=+6
And, since
q+=+10+-+d
q+=+4
He has 4 quarters
check answer:
(2) 10d+%2B+25q+%2B+30+=+10q+%2B+25d
10%2A6+%2B+25%2A4+%2B+30+=+10%2A4+%2B+25%2A6
60+%2B+100+%2B+30+=+40+%2B+150
190+=+190
OK




Miscellaneous_Word_Problems/241880: snookers lumber can convert logsinto either lumber or plywood. In a given day, the mill turns out thre times as mny units of plywood as lumber. It makes a profit of $30 on a unit of lumber and $40 on a unit of plywood. Howmany of each must be produced and sold in orer to make a profit of $15,600?
1 solutions

Answer 177129 by josmiceli(9645) About Me  on 2009-11-22 22:49:16 (Show Source):
You can put this solution on YOUR website!
Let a = units/day of lumber needed
Let b = units/day of plywood needed
given:
(1) b+=+3a
(2) 30a+%2B+40b+=+15600
---------------------------------------
Substitute (1) in (2)
(2) 30a+%2B+40%2A%283a%29+=+15600
30a+%2B+120a+=+15600
150a+=+15600
a+=+104
b+=+3a
b+=+3%2A104
b+=+312
104 = units/day of lumber needed
312 = units/day of plywood needed


Equations/241609: I have two question.
write the equation of the line. Through (8,-9), perpendicular to 7x + 9y = -25
question #2 is through (-6,-7) parallel to -2x + 7y=26
Can you please Help?????
1 solutions

Answer 176975 by josmiceli(9645) About Me  on 2009-11-22 12:12:52 (Show Source):
You can put this solution on YOUR website!
The rule is: if you have a line with slope = m, then
ANY line perpendicular to it will have slope = -%281%2Fm%29
So, first you have to find the slope of your line.
Get it into the form y+=+mx+%2B+b where m = slope
7x+%2B+9y+=+-25
9y+=+-7x+-+25
y+=+-%287%2F9%29%2Ax+-+25%2F9
You can see that m+=+-%287%2F9%29
Now you have to find -%281%2Fm%29
Divide both sides by m
1+=+-%287%2F9%29%2A%281%2Fm%29
Divide both sides by 7%2F9
1%2F%287%2F9%29+=+-%281%2Fm%29
9%2F7+=+-%281%2Fm%29
So, ANY line perpendicular to the given line will have this slope
The line you're looking for passes through (8,-9)
The formula is
%28y+-+y%5B1%5D%29%2F%28x+-x%5B1%5D%29+=+m where( x%5B1%5D, y%5B1%5D) is the given point
%28y+-+%28-9%29%29%2F%28x+-+8%29+=+9%2F7
Multiply both sides by x-8
y+%2B+9+=+%289%2F7%29%2A%28x-8%29
y+%2B+9+=+%289%2F7%29%2Ax+-+72%2F7
y+=+%289%2F7%29%2Ax+-+63%2F7+-+72%2F7
y+=+%289%2F7%29%2Ax+-+135%2F7 answer
Or, if you like,
9x+-+7y+-+135+=+0
I'll plot both lines


Quadratic_Equations/241607: Molly’s age is twice Anita’s. If the sum of the squares of their ages is 80, then translate these words into an algebraic equation to determine their ages?
1 solutions

Answer 176967 by josmiceli(9645) About Me  on 2009-11-22 11:41:31 (Show Source):
You can put this solution on YOUR website!
m+=+2a
m%5E2+%2B+a%5E2+=+80
By substitution,
%282a%29%5E2+%2B+a%5E2+=+80
4a%5E2+%2B+a%5E2+=+80
5a%5E2+=+80
a%5E2+=+16
a+=+4
and, since
m+=+2a
m+=+2%2A4
m+=+8
Molly is 8 and Anita is 4


Graphs/241600: How do you solve this type of absolute value equation? It has a number outside the absolute value symbol that would indicate the distributive property, but it isn't matching the answers in the back when I tried that. Here is an example:
3/5 |3x+2| +5 = y
Would you try the 2 solutions, one positive and one negative? But I can't see how to do that when you don't know what x is.
Thanks!
1 solutions

Answer 176966 by josmiceli(9645) About Me  on 2009-11-22 11:37:23 (Show Source):
You can put this solution on YOUR website!
The way I approach it is to disassemble it, then put it back together
%283%2F5%29%2Aabs%283x%2B2%29+%2B5+=+y
I'll disregard the 5 and the 3%2F5 for now
abs%283x%2B2%29+=+y
y can never be negative
When x+=+-%282%2F3%29, y+=+0
I'll plot it
+graph%28+400%2C+400%2C+-4%2C+4%2C+-4%2C+4%2C+abs%283x%2B2%29%29+
Now I'll factor in the 3%2F5, and plot that
+graph%28+400%2C+400%2C+-4%2C+4%2C+-4%2C+4%2C++%283%2F5%29%2Aabs%283x%2B2%29%29+
The plot is spread out, since y is now less for every x
Now I'll add 5 to the last plot
+graph%28+400%2C+400%2C+-4%2C+4%2C+-2%2C+8%2C+%283%2F5%29%2Aabs%283x%2B2+%29+%2B+5%29+
Since there are 2 variables, the solution is the plot
Do you want inequalities? You can get those from the plot, too


Money_Word_Problems/241518: P dollars invested at interest rate r compounded annually for 5 years increases to an amount A = P(1 + r)^5. If an investment of $1000 is to increase to an amount greater than $1400 in 5 years, then the interest rate must be greater than what percentage?
1 solutions

Answer 176892 by josmiceli(9645) About Me  on 2009-11-21 22:47:36 (Show Source):
You can put this solution on YOUR website!
A+=+P%2A%281+%2B+r%29%5E5
P+=+1000
A+=+1400
1400+=+1000%2A%281+%2B+r%29%5E5
1.4+=+%281+%2B+r%29%5E5
Take the log base 10 of both sides
log%281.4%29+=+5%2Alog%281+%2B+r%29
.146+=+5%2Alog%281+%2B+r%29
log%281+%2B+r%29+=+.0292
10%5E.0292+=+1+%2B+r
1.07+=+1+%2B+r
r+=+.07
The interest rate has to be greater than 7%