Answer: Caitlyn spent 3 hours biking and 4 hours walking to the mall.
Explanation:
Let t represent the time that Caitlyn spent biking to the mall, traveling 14 mph.
Distance = speed × time
Distance covered on his way to the mall is
14 × t = 14t.
If the total trip to the mall took 7 hours, it means that the time spent by Caitlyn in walking the rest of the way, traveling 7 mph would be (7 - t) hours. Distance covered by walking is
7(7 - t)
The total trip was 70 miles. It means that
14t + 7(7 - t) = 70
14t + 49 - 7t = 70
14t - 7t = 70 - 49
7t = 21
t = 21/7 = 3 hours
Caitlyn spent 3 hours biking to the mall.
Caitlyn spent 7 - 3 = 4 hours walking to the mall.