Elizabeth changed her time for the mile walk from 30 minutes to 24 minutes. What was the percent of change?

-20%

Basically, we are trying to find the change from 30 to 24 in terms of percent. We do this in three steps:

1) Find the difference between 30 and 24 as a number.

2) Divide the result from Step 1 by the starting number 30.

3) Multiply the result from Step 2 by 100 to get it in terms of percent.

The three steps above can be made into a formula. Thus, to find the percent change from 30 to 24, we use this formula:

((Y-X)/X)*100 = Percent Change

X is the starting number 30, and Y is the ending number 24 that it changed to. When we enter these numbers into the formula, we get:

((24-30)/30)*100 = -20.00%

Thus, the answer to the question "What is the Percent Change from 30 to 24?" is:

-20.00%

If the diameter is 8 than the radius is 4 because 2r or 2*radius equals the diameter. 4*2=8. 8/2=4.