Answer:
320 minutes was her time on the previous race
Step-by-step explanation:
Let the time spent on the previous race be x minutes.
Given that at her most recent race, Sue finished in 272 minutes which is 15% less time than the previous race then
x - 15% * x = 272
x - 0.15x = 272
0.85x = 272
x = 272/0.85
x = 320 minutes
