Answer: 60%
Explanation:
Given: Climbing rate at the end of week 1 = 25 steps per minute.
Climbing rate at the end of week 4 = 60 steps per minute
The percent increase in Maggie's rate of climbing steps from the end of week 1 to the end of week 4 will be :

Hence, the percent increase in Maggie's rate of climbing steps from the end of week 1 to the end of week 4 = 60%