# Solve my math word problem

I have a math word problem involving percents. What percentage difference is the number 25 from the number 40?

### 6 Answers

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1. The percentage difference between two numbers is usually defined like this: |A-B|/B*100

where A is the number in question, (in this case the 25), and B is the number to which 25 is being compared, in this case, the 40.

The vertical bars in |A-B| mean after subtracting the two numbers, take the absolute value of the result. (In case you don’t remember, an absolute value means to drop a minus sign if the answer is negative.)

So, to find your answer, 25-40 is -15, and the absolute value of -15 is 15.

Now, divide the 15 by 40 to get 0.375.

Finally, multiply the 0.375 by 100 to convert it to a percent (0.375 times 100 is 37.5).

Or, 25 differs from 40 by 37.5%.

Sometimes the percentage difference can also mean the “percentage change” between two numbers, in which case you could say:

There is a 37.5% change between 25 and 40.

1. 100 cents are equal to 1 dollar.
30 dollars = 3000 cents

Let x is amount of 10-cents coins and y is amount of 25-cents coins.

x+y = 380
10x+5y = 3000

Solving the system of equations:

y = 380 – x

10x+5y = 3000
y = (3000 – 10x)/5
y =600 – 2x

380 – x = 600 – 2x
-x + 2x = 600 – 380
x = 220

y = 380 – 220
y = 160

Amanda has saved 160 coins at 5 cents.