On Jiamin's trip to Wisconsin, her average rate of speed for the whole 5-hour trip was 62 miles per hour. For the first two hour
s of her trip, she kept her average speed at 50 miles per hour Then she realized she was going to be late, so she started driving faster. What was her average speed for the last three hours of her trip?
The total length of Jiamin's trip was distance = speed × time distance = (52 mi/h) × (5 h) = 260 mi
The distance Jiamin traveled in her first 2 hours was distance = (50 mi/h) × (2 h) = 100 mi
That means she traveled the last (260 -100) mi = 160 mi in the remaining 3 hours. Her average speed for that portion of the trip was speed = distance / time speed = (160 mi) / (3 h) = (160/3) mi/h ≈ 53 1/3 mi/h
Jiamin's average speed for the last 3 hours of her trip was 53 1/3 mi/h.
