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

Updated on June 27, 2017 in
Homework Help

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.

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 savedĀ 160 coins at 5 cents.

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