Please, share the goal of the problem. If Carrie works 40 hours per week and spends 15% of her time at the register, how much time does she NOT spend at the register?
Subtract 15% from 100%; the result is 85%. Now find 85% of 40 hours:
0.85(40 hours) = 34 hours.
Please note that I invented part of this problem. Next time, share all of the info so that someone can help you solve YOUR particular problem.
56 miles : 1 hour
/2. /2
28 miles : 30 minutes
56+28. 1h+30m
84 miles : 1 hour 30 minutes
84 is the answer