How long must a driver take to drive the final 70 miles of a trip if he wants to average 50 miles an hour for the entire trip and during the first part of the trip he drove 50 miles in {1 ☓ (1 ÷ 2)} hours?
Note
Total distance = (70 + 50) miles = 120 miles.
Average speed = 50 miles/hour.
Required time to journey = (120 ÷ 50)hr
= 125 hr
= 2hr 24 min
Time taken to cover 50 miles = {1 ☓ (1 ÷ 2)}hr = 1hr 30 min.
∴ Remaining time = (2 hr 24 min - 1 hr 30 min) = 54 min.