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logarithm/549639: the half-life of a particular element is 4 days. after 20 days a sample has been reduced to a mass of 0.375g. what was the initial mass of the sample?
1 solutions

Answer 357926 by ankor@dixie-net.com(15656) About Me  on 2011-12-21 19:35:15 (Show Source):
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the half-life of a particular element is 4 days.
after 20 days a sample has been reduced to a mass of 0.375g.
what was the initial mass of the sample?
:
the radioactive decay formula: A = Ao*2^(-t/h), where
A = resulting amt after t time
Ao = initial amt
t = time
h = half-life of substance
:
Ao*2^(-20/4) = .375
Ao*2^(-5) = .375
Ao*.03125 = .375
Ao = .375%2F.03125
Ao = 12 grams, the initial mass of the sample
:
:
Check this on your calc: enter 12*2^(-20/4) result .375


Inequalities/549601: I cannot find an example even similar to this one. Please help...
1/x+2/x^2 is less than or equal too 1/x-1
1 solutions

Answer 357919 by ankor@dixie-net.com(15656) About Me  on 2011-12-21 17:44:50 (Show Source):
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1/x+2/x^2 is less than or equal too 1/x-1
Assume the problem is:
1%2Fx + 2%2Fx%5E2 <= 1%2F%28%28x-1%29%29
we can put the left side over a single denominator
%28%28x%2B2%29%29%2Fx%5E2 <= 1%2F%28%28x-1%29%29
Cross multiply
(x+2)(x-1) <= x^2
FOIL
x^2 + x - 2 >= x^2
x^2 - x^2 + x - 2 <= 0
x - 2 <= 0
x <= +2, however x cannot = 1, (division by 0)


Age_Word_Problems/549503: Susi is 25 years younger then her mother.

In 7 years the mother will be 5 times older then Susi.
cant figure this one out How old is the mother when she's 5times older and how old is susi???????????

1 solutions

Answer 357815 by ankor@dixie-net.com(15656) About Me  on 2011-12-21 07:55:50 (Show Source):
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Susi is 25 years younger then her mother.
In 7 years the mother will be 5 times older then Susi.
:
There is a reason why you can't figure this out, it is impossible
We will do the problem and see that
;
s = Susi's present age,
m = Mother's age
:
Write an equation for each statement:
:
"Susi is 25 years younger then her mother."
s = m - 25
or we can say
m = s + 25
:
In 7 years the mother will be 5 times older then Susi.
m + 7 = 5(s + 7)
Simplify
m + 7 = 5s + 35
m = 5s + 35 - 7
m = 5s + 28
now, replace m with (s+25), from the 1st statement
s + 25 = 5s + 28
25 - 28 = 5s - s
-3 = 4s
s = -3%2F4, a nonsensical solution, perhaps they meant 7 year ago!!
or they meant
"In 7 years the mother will be 5 times older then Susi is now!"
:
Let me know what you think. C


Numbers_Word_Problems/549427: the sum of two numbers is one-hundred seventy-eight. The difference between the number is six. what is the product of the two numbers.
1 solutions

Answer 357769 by ankor@dixie-net.com(15656) About Me  on 2011-12-20 21:44:28 (Show Source):
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the sum of two numbers is one-hundred seventy-eight.
a + b = 178
:
The difference between the number is six.
a - b = 6
:
Use elimination here,
a + b = 178
a - b = 6
-----------adding eliminates b, find a
2a = 184
a = 184/2
a = 92
then
92 + b = 178
b = 178 - 92
b = 86
:
what is the product of the two number, I'll let you find the product


Rational-functions/549121: A SQUARE AND A RECTANGLE HAVE THE SAME AREA. THE LENGTH OF THE RECTANGLE IS 8 MORE THAN A SIDE OF THE SQUARE, AND THE WIDTH OF THE RECTANGLEIS 4 LESS THAN A SIDE OF THE SQUARE. FIND A SIDE OF THE SQUARE.
NOTE: THIS IS A QUADRATIC EQUATION.
1 solutions

Answer 357766 by ankor@dixie-net.com(15656) About Me  on 2011-12-20 21:33:56 (Show Source):
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A SQUARE AND A RECTANGLE HAVE THE SAME AREA.
THE LENGTH OF THE RECTANGLE IS 8 MORE THAN A SIDE OF THE SQUARE, AND THE WIDTH OF THE RECTANGLEIS 4 LESS THAN A SIDE OF THE SQUARE.
FIND A SIDE OF THE SQUARE.
:
Let x = the side of the square
then
x^2 = the area of the square
:
(x+8) = the length of the rectangle
(x-4) = the width of the rectangle
then FOIL
(x+8)(x-4) = x^2 - 4x + 8x - 32
x^2 + 4x - 32 = the area of the rectangle
:
Given the areas areas are equal
x^2 + 4x - 32 = x^2
Combine the x^2's on the left
x^2 - x^2 + 4x - 32 = 0
4x = 32
x = 32/4
x = 8 units is the side of the square
:
:
See if this is right
(8+8) * (8-4) = 8^2
16 * 4 = 64; confirms our solution of x=8


Finance/549276: A DVD costs 7 times what you get when if you add the number of $ in it's price to the number of cents. This gives it's price in cent . What is it ? Thanks.
1 solutions

Answer 357763 by ankor@dixie-net.com(15656) About Me  on 2011-12-20 21:22:18 (Show Source):
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A DVD costs 7 times what you get when if you add the number of $ in it's price to the number of cents.
This gives it's price in cent. What is it?
:
Let d = no. of dollars
Let c = no. of cents
:
100(d+.01c) = 7(d+c)
100d + c = 7d + 7c
100d - 7d = 7c -c
93d = 6c
c = 93%2F6d
reduce the fraction
c = 31%2F2d
we can see that an integer solution is possible when d = 2, then c = 31
Actually we have 3 integer solutions from this equation (c has to be less than 100)
DVd cost:
d . c
$2.31, 7(2+31) = 231 cents
$4.62, 7(4+62) = 462 cents
$6.93, 7(6+93) = 693 cents


Rectangles/549412: if one side of a square is increased by 3 inches and the adjacent side is decreased by 2 inches, a rectangle is formed whose are is equal to the area of the square. Find a side of the square
1 solutions

Answer 357749 by ankor@dixie-net.com(15656) About Me  on 2011-12-20 20:16:13 (Show Source):
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if one side of a square is increased by 3 inches and the adjacent side is decreased by 2 inches, a rectangle is formed whose are is equal to the area of the square.
Find a side of the square
:
Let x = the side of the square
then
x^2 = the area of the square
:
(x+3) = length of the rectangle
and
(x-2) = width of the rectangle
then
(x+3)*(x-2) = x^2 + x - 6, the area of the rectangle
:
Rect area = square area
x^2 + x - 6 = x^2
x^2 - x^2 + x = 6
x = 6 inches is the side of the square
:
:
See if this flies:
(6+3)*(6-2) = 6^2
9 * 4 = 36


test/549274: simon ordered 200 boxes of Fuji apples from china.he paid $28 per box for the apples. there were 60 fruits in each box and he expected 15% of them yo spoil. if he wants to make a profit of 80% on cost what should be the selling price per fruit?

1 solutions

Answer 357747 by ankor@dixie-net.com(15656) About Me  on 2011-12-20 20:06:39 (Show Source):
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simon ordered 200 boxes of Fuji apples from china.he paid $28 per box for the apples.
there were 60 fruits in each box and he expected 15% of them yo spoil.
if he wants to make a profit of 80% on cost what should be the selling price per fruit?
:
Find the total cost of the apples: 28 * 200 = $5,600
Find how much he should receive to realize an 80% profit: 1.80*5600 = $10,080
:
Find how many boxes he has after 15% of them spoil: .85(200) = 170 boxes
Find how many apples he has: 170*60 = 10200 apples
:
Let x = amt he should charge to make the required amt
10200x = $10080
x = 10080%2F10200%7C
x = $.99 per apple to make at least the required amt of $10,080


Systems-of-equations/549413: Solve the given system of linear equations for X:
4X + y= -11 and X + 2y= 6
Please show how you get the answer
Thank you,
Natasha
1 solutions

Answer 357743 by ankor@dixie-net.com(15656) About Me  on 2011-12-20 19:44:22 (Show Source):
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Solve the given system of linear equations for X:
4X + y = -11
X + 2y = 6
;
We can use elimination here, multiply the 1st equation by 2, subtract the 2nd equation
8X +2y = -22
X + 2y = 6
-------------subtraction eliminates y, find x
7x = -28
x = -28/7
x = -4
:
Find y using the 2nd equation, replace x with -4
-4 + 2y = 6
2y = 6 + 4
2y = 10
y = 10/2
y = 5
:
:
Check our solution of x=-4, y=5, using the 1st equation
4X + y = -11
4(-4) + 5 = -11
-16 + 5 = -11; confirms our solutions


Money_Word_Problems/549420: A total of $15,000 is invested in two accounts. One of the two accounts pays 8% per year, and the other account pays 12% per year. If the total interest paid in the first year is $1,600, how much was invested in each account?
Two answers are needed amount for 8% account and money made for 12% account.
Please help!
1 solutions

Answer 357742 by ankor@dixie-net.com(15656) About Me  on 2011-12-20 19:36:40 (Show Source):
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Let x = amt invested at 8%
Let y = amt invested at 12%
:
Write an equation for each statement:
:
A total of $15,000 is invested in two accounts.
x + y = 15000
or
x = (15000-y), we can use this form for substitution
:
One of the two accounts pays 8% per year, and the other account pays 12% per year.
If the total interest paid in the first year is $1,600,
.08x + .12y = 1600
substitute (15000-y) for x, find y
.08(15000-y) + .12y = 1600
1200 - .08y + .12y = 1600
-.08y + .12y = 1600 - 1200
.04y = 400
y = 400/.04
y = $10,000 invested at 12%
then
15000 - 10000 = $5,000 invested at 8%
:
:
You can check this out
.08(5000) + .12(1000) =




Geometry_Word_Problems/549355: I am building a shed. I can use 400 square feet. I need to know height, width &I length it can be.
1 solutions

Answer 357741 by ankor@dixie-net.com(15656) About Me  on 2011-12-20 19:26:32 (Show Source):
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How about 20 by 20 by 8 ft high?


Rational-functions/549119: If one side of a square is increased by 4 feet and an adjacent side is decreased by two feet,a rectangle is formed whose area is 12 square feet more than the area of the original square.Find the length of a side of the square.
1 solutions

Answer 357682 by ankor@dixie-net.com(15656) About Me  on 2011-12-20 14:32:53 (Show Source):
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If one side of a square is increased by 4 feet and an adjacent side is decreased by two feet, a rectangle is formed whose area is 12 square feet more than the area of the original square.Find the length of a side of the square.
:
Let x = the side of the original square
and
x^2 = area of the square
then
(x+4) = new length of the rectangle
and
(x-2) = new width
then the area of the rectangle
(x+4)*(x-2) = x^2 - 2x + 4x - 8 = x^2+2x-8
;
"a rectangle is formed whose area is 12 square feet more than the area of the original square."
x^2 + x - 8 - x^2 = 12
2x = 12 + 8
2x = 20
x = 10 ft is the side of the original square
:
:
:
See if this checks out
(14*8) - (10*10) =
112 - 100 = 12


Travel_Word_Problems/549294: A picture has a height that is 4/3 its width. It is to be enlarged to have an area of 192 square inches. What will be the dimensions of the enlargement?.
1 solutions

Answer 357595 by ankor@dixie-net.com(15656) About Me  on 2011-12-20 08:35:50 (Show Source):
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A picture has a height that is 4/3 its width. It is to be enlarged to have an area of 192 square inches. What will be the dimensions of the enlargement?.
:
Let x = the value of the multiplier
then the dimensions of the picture will be: 4x by 3x
:
the area
4x * 3x = 192
12x^2 = 192
x^2 = 192%2F12
x^2 = 16
x = 4 is the multiplier
:
4*4 = 16 is the length
4*3 = 12 is the width


Triangles/549011: An airplane is flying at an elevation of 12,000 feet before diving at an angle of depression of 45 degrees for 25 seconds. The plane is traveling at an average rate of 260 miles per hour during the dive. At what elevation does the plane end the dive?
1 solutions

Answer 357593 by ankor@dixie-net.com(15656) About Me  on 2011-12-20 08:29:50 (Show Source):
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An airplane is flying at an elevation of 12,000 feet before diving at an angle of depression of 45 degrees for 25 seconds. The plane is traveling at an average rate of 260 miles per hour during the dive. At what elevation does the plane end the dive?
:
This can be solved as a right triangle using the sine of 45 degrees, where:
the change altitude (a) is the side opposite and
the distance traveled in the dive is the hypotenuse (h)
:
We want the elevation change in feet.
Change distance of the dive to feet traveled in 25 seconds: (3600 sec in 1 hr)
h = %28%28260%2A5280%29%29%2F3600 * 25 = 9533.33 ft
:
sin(45) = a%2F9533.33
a = sin(45)*9533.33
a = 6741.1 ft change in elevation
therefore
12000 - 6741.1 = 5,258.9 ft altitude at the end of the dive


Travel_Word_Problems/549209: A tire of a moving bicycle is 18 inches in radius. If the tire is making 3 rotations per second, find the bicycle's speed in miles per hour.
What I have tried:
Distance = 2 pi r
2 pi 18 = 2 pi in.

1 solutions

Answer 357541 by ankor@dixie-net.com(15656) About Me  on 2011-12-19 22:02:10 (Show Source):
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A tire of a moving bicycle is 18 inches in radius.
If the tire is making 3 rotations per second, find the bicycle's speed in miles per hour.
:
Find no. of inches traveled in 1 hr, divide by no. of inches in a mile.
%28%283%2A2%2Api%2A18%2A3600%29%29%2F%28%2812%2A5280%29%29 = 19.27 mph


Triangles/549015: You are stationed at a radar base and you observe an unidentified airplane at an alititude of 6000 meters. The plane is flying towards the radar base at an angle of elevation of 30 degrees. After exactly one minute, the radar sweep reveals that the plane is now at an angle of elevation of 60 degrees and it is maintaining the same altitude. What is the speed of the plane in meters per second?
1 solutions

Answer 357465 by ankor@dixie-net.com(15656) About Me  on 2011-12-19 16:52:40 (Show Source):
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an unidentified airplane at an alititude of 6000 meters.
The plane is flying towards the radar base at an angle of elevation of 30 degrees.
After exactly one minute, the radar sweep reveals that the plane is now at an angle of elevation of 60 degrees and it is maintaining the same altitude.
What is the speed of the plane in meters per second?
:
Use the tangent of the angle to find the distance (d) to a point directly below plane:
when the angle is 30 degrees
tan(30) = 6000%2Fd
d1 = 6000%2Ftan%2830%29
d1 = 10392.3 meters
when the angle is 60 degrees
tan(60) = 6000%2Fd
d2 = 6000%2Ftan%2860%29
d2 = 3464.1 meters
:
d1 - d2 = distance traveled by aircraft in 1 min
10392.3 - 3464.1 = 6928.2 m/min
convert to m/sec
6928.2%2F60 = 115.47 m/sec
:


Miscellaneous_Word_Problems/548435: Doppler radar shows an electrical storm 2.5 miles away. If you see te lightning from this storm, how long will it be before you hear the thunder?
1 solutions

Answer 357093 by ankor@dixie-net.com(15656) About Me  on 2011-12-18 07:32:49 (Show Source):
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Doppler radar shows an electrical storm 2.5 miles away.
If you see the lightning from this storm, how long will it be before you hear the thunder?
:
Using the speed of sound as 1100 ft/sec
:
%282.5%2A5280%29%2F1100 = 12 sec


Average/548538: I have a 92 on a quiz that is worth 5 percent of my grade what is the actual points I have for this quiz and how would I solve this type of problem to figure out my other points/grades? Thanks!
1 solutions

Answer 357050 by ankor@dixie-net.com(15656) About Me  on 2011-12-17 21:54:38 (Show Source):
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I have a 92 on a quiz that is worth 5 percent of my grade
what is the actual points I have for this quiz and how would I solve this type of problem to figure out my other points/grades?
:
5% really means it is only 1/20 of the grade, and example, say up to this quiz you have an 86 average, which is 95% of the grade; you want to know what affect this quiz of 92 will effect the overall average grade
:
Av = %2819%2886%29%2B92%29%2F20
Av = %281634%2B92%29%2F20
Av = 1726%2F20
Av = 86.3, it will only raise the average .3 %


Graphs/548482: Good afternoon,
Hello i have homework on slope intercept equations and i needed help. Here's the problem it says 3x-2y=18 i have to put that in slope intercept form.
1 solutions

Answer 357048 by ankor@dixie-net.com(15656) About Me  on 2011-12-17 21:09:53 (Show Source):
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3x - 2y = 18
subtract 3x from both sides
-2y = -3x + 18
Y has to be positive, multiply both sides by -1
2y = 3x - 18
y has to have a coefficient of 1, Divide both sides by 2
y = 3%2F2x - 9; the slope intercept form


Radicals/548513: A picture frame measures 26 in. by 24 in.. There is 575 in. squared of picture showing. The frame is of uniform thickness. Find the thickness of the frame.
1 solutions

Answer 357042 by ankor@dixie-net.com(15656) About Me  on 2011-12-17 19:55:05 (Show Source):
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A picture frame measures 26 in. by 24 in..
There is 575 in. squared of picture showing.
The frame is of uniform thickness. Find the thickness of the frame.
:
Let x = the width of the frame
then
(26-2x) by (24-2x) is the dimensions of the pictures, which is 575 sq/in
therefore, the area equation:
(26-2x)*(24-2x) = 575
FOIL
624 - 52x - 48x + 4x^2 = 575
Combine like terms to form a quadratic equation:
4x^2 - 100x + 624 - 575 = 0
4x^2 - 100x + 49 = 0
We can us the quadratic formula, but this will factor to
(2x-49)(2x-1) = 0
two solutions, but only one will make sense
2x = 49
x = 49/2
x = 24.5", obviously this could not be the width of frame
and
2x = 1
x = .5 inch is the reasonable width of the frame
:
:
We can confirm this by finding the area using x=.1, then 2x = 1, so we have
(26+1)(24+1) = 675 for the overall area, like was given


Graphs/548484: Good afternoon,
Hello i have homework on slope intercept equations and i needed help. Here's the problem it says line parallel to y= 3x=4 with the y- intercept of 10 i have to put that in slope intercept form.
1 solutions

Answer 357024 by ankor@dixie-net.com(15656) About Me  on 2011-12-17 16:51:31 (Show Source):
You can put this solution on YOUR website!
Here's the problem it says line parallel to y= 3x+4 with the y- intercept of 10 i have to put that in slope intercept form.
:
Parallel lines have the same slope, therefore the equation for this equation is:
y = 3x + 10
as you can see
+graph%28+300%2C+200%2C+-10%2C+10%2C+-20%2C+20%2C+3x%2B4%2C+3x%2B10%29+


Rate-of-work-word-problems/548491: one pipe can fill a cooling tank in 3 hours less that a second pipecan.if the two pipes together can fill seven-ninths of the tank in 4 hours ,how many hours would it take each pipe alone to fill the tank
1 solutions

Answer 357023 by ankor@dixie-net.com(15656) About Me  on 2011-12-17 16:39:34 (Show Source):
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one pipe can fill a cooling tank in 3 hours less that a second pipe can.
if the two pipes together can fill seven-ninths of the tank in 4 hours,
how many hours would it take each pipe alone to fill the tank
:
Let p = one pipes filling time
then
(p+3) = another pipes filling time
:
Let a full tank = 1
:
4%2Fp + 4%2F%28%28p%2B3%29%29 = 7%2F9
Multiply by 9p(p+3), results
9(p+3)(4) + 9p(4) = 7p(p+3)
36p + 108 + 36p = 7p^2 + 21p
72p + 108 = 7p^2 + 21p
:
combine like terms on the right
0 = 7p^2 + 21p - 72p - 108
7p^2 - 51p - 108 = 0; a quadratic equation
You can use the quadratic equation here, but this will factor to:
(7p + 12)(p - 9) = 0
the positive solution is all we want here
p = 9 hrs time for one pipe alone
and
12 hrs for the other pipe alone
:
:
Let's check this out, using decimals
4%2F9 + 4%2F12 =
.444 + .333 = .777 which is very close to 7/9


Travel_Word_Problems/548415: after 30 minutes a car moving at a constant speed has traveled 25 miles. given that the distance varies directly as time, how far will the car travel in 140 minutes?
1 solutions

Answer 357019 by ankor@dixie-net.com(15656) About Me  on 2011-12-17 16:22:05 (Show Source):
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after 30 minutes a car moving at a constant speed has traveled 25 miles. given that the distance varies directly as time, how far will the car travel in 140 minutes?
:
30%2F140 = 25%2Fd
Cross multiply 140d = 30*25
30d = 140*25
30d = 3500
d = 3500%2F30
d = 116.67 miles
:
:


Graphs/548384: Question: Write an equation for the points (-8,-2), (0,-2), (8,-2), which are plotted on the graph below.
*I was provided a graph with the plotted points which I gave in my question above. Not sure how I would go about, even if possible, providing a graph for my question. Hope you understand my question and can help me.
1 solutions

Answer 356971 by ankor@dixie-net.com(15656) About Me  on 2011-12-17 08:55:57 (Show Source):
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This is a horizontal line which is: y = 0x - 2, or just y = -2


Miscellaneous_Word_Problems/548243: Suppose I can mow the lawn at the park by my house in 8 hours. It takes my neighbor 10 hours to mow he same lawn. If I started mowing at 8am, then he came and began helping me at 10am, what time would we finish mowing the lawn?
1 solutions

Answer 356928 by ankor@dixie-net.com(15656) About Me  on 2011-12-16 21:00:16 (Show Source):
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Suppose I can mow the lawn at the park by my house in 8 hours.
It takes my neighbor 10 hours to mow he same lawn.
If I started mowing at 8am, then he came and began helping me at 10am, what time would we finish mowing the lawn?
:
Let t = your mowing time
then
(t-2) = neighbor's mowing time
:
Let the completed job = 1
:
t%2F8 + %28t-2%29%2F10 = 1
multiply by 40 to clear the denominators, results:
5t + 4(t-2) = 40
5t + 4t - 8 = 40
9t = 40 + 8
9t = 48
t = 48/9
t = 51%2F3 hrs or 5 hrs 20 min, working together
You would finish at: 8:00 + 5:20 = 1:20 PM
:
:
See if this checks out
5.33%2F8 + %283.33%29%2F10 =
.67 + .33 = 1


Percentage-and-ratio-word-problems/547925: My question:
When five new girls joined a class, the percent of girls increased from 40% to 50%. What is the number of boys in the class?
What I tried:
1.If there is 50% girls in the class, then there is 50% boys, so however many girls are in the class, is how many boys are in the class. 2.I said that the ORIGINAL total class accumulation, was 45 kids, because if there is 25 boys in the class, and 20 girls in the class, the boy population is 60%, and the girl's is 40%. However, I said that if I increase the girl population by 10%, I would need to add five girls, so now there is 25 girls, and 25 boys (50% boys and girls) What am I doing wrong? Can you help me solve it? 3. My teacher said this was incorrect, and I got a 5/10 on this problem; 3 for work, 1 for solution, and 1 for check. If you could help me, I would appreciate it! Thanks a lot!!!
1 solutions

Answer 356857 by ankor@dixie-net.com(15656) About Me  on 2011-12-16 13:49:46 (Show Source):
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When five new girls joined a class, the percent of girls increased from 40% to 50%.
What is the number of boys in the class?
:
Use algebra to solve this:
:
Let g = original number of girls in the class
Let b = no. of boys
then
(g+b) = original number in the class
:
Originally
g%2F%28g%2Bb%29 = .4, (40%)
g = .4(g+b)
g = .4g + .4b
g - .4g = .4b
.6g = .4b
multiply 10 to get rid of the decimal
6g = 4b
:
Add 5 girls equation
%28g%2B5%29%2F%28g%2Bb%2B5%29 = .5
g + 5 = .5(g+b+5)
g + 5 = .5g + .5b + 2.5
g = .5g + .5b + 2.5 - 5
g - .5g = .5b - 2.5
.5g = .5b - 2.5
get rid of the decimal, mult by 2
g = b - 5
replace g with (b-5) in the 1st equation (6g = 4b)
6(b-5) = 4b
6b - 30 = 4b
6b - 4b = 30
2b = 30
b = 15 boys in the class
:
:
Check this:
g = b - 5
g = 15 - 5
g = 10 girls originally
then when 5 girls are added, it will be 15:15


Miscellaneous_Word_Problems/548244: I have a tank that can be filled by a small pipe in 12 hours or by a large pipe in 8 hours. Suppose I start filling the tank with the large pipe for two hours. After that 2 hours is up, I use both pipes and continue filling the tank for a length of time, t. I then turn off the large pipe and it takes 2 more hours to fill the tank with just the small pipe. How long of a time is t?
1 solutions

Answer 356852 by ankor@dixie-net.com(15656) About Me  on 2011-12-16 13:26:27 (Show Source):
You can put this solution on YOUR website!
I have a tank that can be filled by a small pipe in 12 hours or by a large pipe in 8 hours.
Suppose I start filling the tank with the large pipe for two hours.
After that 2 hours is up, I use both pipes and continue filling the tank for a length of time, t.
I then turn off the large pipe and it takes 2 more hours to fill the tank with just the small pipe.
How long of a time is t?
:
Let the completed task = 1 (a full tank)
:
from the given information:
(t+2) = filling time of the large pipe
and
(t+2) = filling time of the smaller
:
%28t%2B2%29%2F12 + %28t%2B2%29%2F8 = 1
Multiply by 24, results:
2(t+2) + 3(t+2) = 24
2t + 4 + 3d + 6 = 24
2t + 3t = 24 - 10
5t = 14
t = 14%2F5
t = 2.8 hrs
;
:
See if that checks out
%282.8%2B2%29%2F12 + %282.8%2B2%29%2F8 =
4.8%2F12 + 4.8%2F8 =
.4 + .6 = 1


Triangles/548013: The figure below is an isosceles triangle. The altitude is 5 inches and the congruent sides are 8 inches. Find the length of the base to the nearest tenth of an inch. Show all work and explanations.
I really dont understand this please help!
1 solutions

Answer 356818 by ankor@dixie-net.com(15656) About Me  on 2011-12-16 11:25:17 (Show Source):
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The figure below is an isosceles triangle.
The altitude is 5 inches and the congruent sides are 8 inches.
Find the length of the base to the nearest tenth of an inch.
:
we can use pythag, a^2 + b^2 = c^2
a = 5
b = 1%2F2 the base
c = 8
:
5^2 + b^2 = 8^2
25 + b^2 = 64
b^2 = 64 - 25
b^2 = 39
b = sqrt%2839%29
b = 6.245 * 12.5 inches is the base


Geometry_Word_Problems/547933: Please help me solve this problem.
The sum of the measures of the complement and supplement of an angle is 214 to the 0 power. Find the measure of the angle.
1 solutions

Answer 356712 by ankor@dixie-net.com(15656) About Me  on 2011-12-15 21:55:16 (Show Source):
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The sum of the measures of the complement and supplement of an angle is 214 to the 0 power. Find the measure of the angle.
:
I think you mean degree here, not 214^0, any no. ^0 is equal to 1 and that would not make sense
:
let a = the angle
then
(90-a) = the complement
and
(180-a) = the supplement
;
These are given as = to 214, therefore we have:
(90-a) + (180-a) = 214
Combine like terms
270 - 2a = 214
-2a = 214 - 270
-2a = -56
a = %28-56%29%2F%28-2%29
a = +28 degrees


Mixture_Word_Problems/548035: Can you please help me solve this problem?
"A chemist mixed a 20% alcohol solution with a 12% alcohol solution to obtain 200mL of a 15% alcohol solution. How many mL of the 20% solution did he use?"
1 solutions

Answer 356711 by ankor@dixie-net.com(15656) About Me  on 2011-12-15 21:47:33 (Show Source):
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A chemist mixed a 20% alcohol solution with a 12% alcohol solution to obtain 200mL of a 15% alcohol solution.
How many mL of the 20% solution did he use?"
:
Let x = amt of 20% solutions required
It states the results should be 200 ml, therefore
(200-x) = amt of 12% required
:
Write a decimal equiv mixture equation
:
.20x + .12(200-x) = .15(200)
.20x + 24 - .12x = 30
.20x - .12x = 30 - 24
.08x = 6
x = 6%2F.08
x = 75 ml of 20% solution
:
:
Check this (200-75=125 ml of 12%)
.20(75) + .12(125) = .15(200)
15 + 15 = 30; confirms our solution


Age_Word_Problems/547982: If x units of a product costs C dollars to manufacture and earn revenue of R dollars, the value of x where the expressions for C and R are equal is called the break-even quantity, the number of units that produce zero profit. Find the break-even quantiry when C=14x + 28000 and R=16x
1 solutions

Answer 356710 by ankor@dixie-net.com(15656) About Me  on 2011-12-15 21:39:11 (Show Source):
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Find the break-even quantity when C=14x + 28000 and R=16x
:
This isn't hard, if R = C. we have:
"
16x = 14x + 28000
16x - 14x = 28000
2x = 28000
x = 14000