Question

Find the percent change from the first value to the second.

Answer 1

Answer:

80% increase

Step-by-step explanation:

There are two ways to do this

The first way is to set up a percent proportion

$\frac{72}{x}$ = $\frac{40}{100}$

To find x, we can do:

x = $\frac{72 * 100}{40}$

x = $\frac{7200}{40}$

x = 180

72 is 180% of 40

There is an 80% increase.

The second way to do it (the way I find easier) is to use benchmark fractions:

We look at 40 and 72 and realize that (40 * 2) - 8 = 72

So 200% of 40 - 8 = 72

Then, we find out what percent of 40 is 8.

10% of 40 is 4

so that means 20% of 40 is 8 (10% * 2 = 4 * 2)

Then we do:

80 - 8 = 72

200% - 20% = 180%

72 = 180% of 40

Which is an 80% increase

Let me know if you have any questions