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Percentage-and-ratio-word-problems/296214: A basket contains some apples. Alice takes 1/2 of the apples and then places 15 of the apples back in the basket. Barry then takes 1/2 of the remaining apples and places 10 back in the basket.They find that each of them has the same number of apples. How many apples are left in the basket?
(A) 10 (B) 20 (C) 30 (D) 50 (E) Not enough information
1 solutions
Answer 213497 by richwmiller(9143)   on 2010-04-25 09:23:21 (Show Source):
You can put this solution on YOUR website!(x/2-15)=(x/2+15)/2-10
b =(x/2+15)/2-10
a=x/2-15
k=x-a-b
We only need the first equation to solve for x the number of apples in the beginning
b= barry's apples at end
a= alice's apples at end
k equals number of apples left in basket at end
x= 50 apples in the beginning
a takes 25 and puts 15 back
a=10
basket has 40 now
b takes 20 and returns 10
b=10
basket has 30 now
Barry and Alice each have 10
30 left in the basket
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Equations/296139: A lumber yard can convert logs into either lumber or plywood. In a given day, the mill turns out twice as many units of plywood as lumber. It makes a profit of $20 on a unit of lumber and $45 on a unit of plywood. How many of each unit must be produced and sold in order to make a profit of $11440?
1 solutions
Answer 213454 by richwmiller(9143) on 2010-04-24 22:11:46 (Show Source):
You can put this solution on YOUR website!Same problem different numbers
http://www.algebra.com/algebra/homework/Linear-equations/Linear-equations.faq.question.182987.html
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Functions/296105: I was given this problem to solve:
f(x) = 12/7
Evaluate for f(6).
I cannot see how this is a function, since there is only one variable on the left side of the equation. The answer I submitted was that there was no real solution and I was graded as wrong. Can you tell me how to solve this problem?
1 solutions
Answer 213447 by richwmiller(9143) on 2010-04-24 21:44:08 (Show Source):
You can put this solution on YOUR website!No matter what x is f(x)=12/7
So f(6) is still 12/7
It is a function. y can have many x's (think zeroes or roots) but x can have only one y. So x=12/7 is not a function.
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Expressions-with-variables/296007: A semicircular window of a radius 14 inches is o be laminated with a sunblock coating that costs $.70 per square inch to apply. What is the total cost of coating the window to the nearest cent?
Please show your work. Thanks.
1 solutions
Answer 213395 by richwmiller(9143) on 2010-04-24 18:23:06 (Show Source):
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logarithm/296058: Could you please help me set this problem up. I have searched my algebra book and found nothing and this isn't something we went over in class.
Given information;
Richter scale converts seismographic readings into numbers...according to this function: M(x)= log(x/x*) , Where x*=10^-3
Question;
What is the magnitude of an earthquake whose seismographic reading is 6.5 mm at a distance of 100 kilometers from its epicenter? Round answer to nearest tenth.
I have no idea how to set the above problem up. Where and what do I plug in to even try and answer it?
Could you also check my work on another problems?
Q: Write as a sum and/or differnece of a logarithms. Express powers as factors.
A: 
I wasn't sure if I'm supposed to brake up the  and  with a plus sign like:
(The 13 doesn't sit on the sqrt it sits outside of it.)
If you could shed some light on these problems I would greatly appreciate it.
Thank you in advance.
1 solutions
Answer 213389 by richwmiller(9143) on 2010-04-24 18:13:41 (Show Source):
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Quadratic_Equations/296022: I need help with finding any x-intercepts and the y-intercepts. If no x-intercepts exist, state this.
g(x)=2x^2+3x-1
This is what I have so far
let y=2x^2+3x-1
for y-intercept, let x=0
for x-intercept lrt y=0
2x^2+3x-1=0
x=(-3+sqrt17)/4
1 solutions
Answer 213387 by richwmiller(9143) on 2010-04-24 18:01:41 (Show Source):
You can put this solution on YOUR website!square roots always come in plus and minus pairs.
don't forget
x=(-3-sqrt17)/4
and what happened to
for y-intercept, let x=0
y=2x^2+3x-1
let x=0
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Radicals/296057: Honestly I do not know where to begin with this question I am really stuck,
Since 1988 basic yacht dimensions for the America’s cup competition have satisfied the inequality
L+1.25√S-9.8^3√D≤16.296
NOTE- after the 9.8 the cubed is above the square root not the 8
Where L is the boat’s length in meters (m), S is the sail area in square meters, and D is the displacement in cubic meters. A team of naval architects is planning to build a boat with a displacement of 21.44 cubic meters (m^3), a sail area of 320.13 square meters (m^2) and a length of 21.22 m. Does this boat satisfy the inequality? If the length and displacement of this boat cannot be changed, then how many square meters of sail area must be removed so that the
boat satisfies the inequality?
1 solutions
Answer 213379 by richwmiller(9143) on 2010-04-24 17:35:42 (Show Source):
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Surface-area/296045: From a 17-inch-by-12-inch piece of cardboard, 2.5-inch-square corners are cut out, as shown in the figure above, and the resulting flaps are folded up to form an open box.
What is the volume of the box?
What is the surface area of the box?
1 solutions
Answer 213375 by richwmiller(9143) on 2010-04-24 17:20:06 (Show Source):
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expressions/296047: 19/22 + (-1/2) Im confused on how to get to the solution
1 solutions
Answer 213374 by richwmiller(9143) on 2010-04-24 17:18:22 (Show Source):
You can put this solution on YOUR website!Two things to do:
First plus a minus is minus
19/22-1/2
Now convert 1/2 to x/22
1/2=11/22
19/22-11/22
8/22
4/11
All done.
BTW 4/11 is not a solution. It is a simplification.
Equations have solutions. This is not an equation. Nothing is equal to anything in the original 19/22+(-1/2)
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Linear-equations/296046: Translate the problem into a pair of linear equations in two variables. Sove the equations using either elimination or substitution. State your answer for the specified variable.
I have 2 problems I need help with.
2) An orchard operator must dilute 11 quarts of a 60% insecticide solution by adding water. How many quarts of water should be added to get a mixture that is 2% insecticide?
1 solutions
Answer 213372 by richwmiller(9143) on 2010-04-24 17:11:49 (Show Source):
You can put this solution on YOUR website!Your problems are a great example for the website rules
one problem at a time. Your problems belong in different categories.
One is a distance problem and one is a mixture problem
This can be solved from the view of the insecticide or from the view of the water
First the insecticide.
11*.6=(11+w)*.02
w=319 quarts of water
Notice there is nothing added on the left. Why ? because water has 0% insecticide and 0*w=0
so from the view of the water.
60% insecticide has 40 percent non insecticide.
.4*11+w=(11+w)*.98
319 quarts of water
Using both methods is a good check on your percentages.
Let's say you put .2 instead of .02 the results would not match.
That is quite a reduction from 60% to 2 percent. Are you sure that is right? not 20 percent?
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absolute-value/296032: On a number line, x represents a number that is within 2 units of 12. Which of the following represents this relationship?
A |x + 2| < 12
B. |x + 12| < 2
C. |x – 2| < 12
D. |x – 12| < 2
E. |12 – 2| < x
1 solutions
Answer 213371 by richwmiller(9143) on 2010-04-24 16:56:09 (Show Source):
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Inequalities/296033: If 3 < x < 7 and 4 < y < 7, which of the following best describes the range of values of x – y?
A. –4 < x – y < 3
B. 0 < x – y < 4
C. 3 < x – y < 4
D. 3 < x – y < 7
E. 4 < x – y < 7
1 solutions
Answer 213370 by richwmiller(9143) on 2010-04-24 16:46:29 (Show Source):
You can put this solution on YOUR website!Try some numbers
Let's take the extremes of x and y
x=4 y=6 x-y=-2
x=6 y=4 x-y=2
x=4 y=5 x-y=-1
x=6 y=6 x-y=0
So we see that x-y can be less than zero
so A) is the only one that matches
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Finance/296041: a postal clerk sold 75 stamps for $4.80. Some were 5-cent and some were 8-cent stamps. How many of each kind did he sell?
1 solutions
Answer 213368 by richwmiller(9143) on 2010-04-24 16:34:10 (Show Source):
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Word_Problems_With_Coins/296040: if c = # of cups, p = # of plates, and there are TWICE AS MANY cups then plates,
does 2c = p or does 2p = c ?
1 solutions
Answer 213367 by richwmiller(9143) on 2010-04-24 16:32:10 (Show Source):
You can put this solution on YOUR website!Try not to use non mathematical symbols in math problems. # has to many meanings.
It just leads to confusion.
Your dilemma is quite common in word problems.
If c = # of cups, p = # of plates, and there are TWICE AS MANY cups as plates,
do I write 2c=p or 2p=c?
I will use the same format as you did.
If n= number of nickels and d= number of dimes and there are twice as many nickels as dimes, do I write 2n=d or 2d=n?
Now the way I would have written the problem.
If n= nickels and d= dimes and there are twice as many nickels as dimes,
do I write 2n=d or 2d=n?
2*5=10
so
2*n=d
Does that help?
2c=p
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