An airplane flies twice as fast as a train which covers 60 miles in 80 minutes. What distance will the airplane cover in 20 minutes?
Note
Time taken to cover 60 miles = 80 min = (3 ÷ 4)hrs = 0.75hrs
∴ Speed of the train = {60☓ (3 ÷ 4)}mph = 45 mph.
Speed of the airplane = (2 ☓ 45) mph = 90 mph.
Distance covered by the airplane in 60 min = 90 miles.
Distance covered by the airplane in 20 min = {(90 ÷ 60) ☓ 20} = 30 miles.