Three months ago david could walk 2 miles in 40 minutes. today he can walk 2 miles in 25 minutes . what is the percent of change

First, you need to notice that both numbers can be turned into fractions.

2 miles 40 minutes: 1/20

2 miles 25 minutes: 2/25

Also notice how most percentages are out of 100? So we have half a fraction we need to turn both of the numbers into.

1/20 = ?/100

2/25 = ?/100

The answer to 1/20 is 5/100, and for 2/25, it's 8/100. Now, we need to add both of the percentages.

5 + 8 = 13

Your answer is 13%. I hope this helps! :)