Question

An Air Force plane flew to the

maintenance facility and back. It took one
hour longer to go there than it did to come
back. The average speed on the trip there
was 256 km/h. The average speed on the
way back was 320 km/h. How many
hours did the trip there take?

Answer 1

5 hours

Explanation:

Time taken for trip : t + 1

Time taken for return : t

Avg. speed (trip) : 256 km/h

Avg. speed (return) : 320 km/h

The distances covered on both trips are equal.

⇒ Distance (trip) = Distance (return)

⇒ Speed (trip) × time (trip) = Speed (return) × time (return)

⇒ (256)(t + 1) = (320)(t)

⇒ 256t + 256 = 320t

⇒ 64t = 256

⇒ t = 4 hours

Time (trip) = t + 1 = 4 + 1 = 5 hours