A person wishes to reach his destination 90 km away in 3 hours … His average speed for the rest of the journey should be?
Note
Time is taken to travel 45 km = (45 ÷ 20)hr = 2 hr 15 min.
Remaining time = (3 hr - 2hr 15 min) 45 min
Hence, the required speed = (45 ÷ 45)km/min = 1 km/min.