A cruise ship traveled to Guam and back.

Question

A cruise ship traveled to Guam and back. The trip there took seven hours and the trip back took five hours. It averaged 4 km/h faster on the return trip than on the outbound trip. Find the cruise ships's average speed on the outbound trip.

Answer 1

Let v be the speed of the ship going to Guam.  The return speed is (v + 4) coming back.

 

Let d be the distance to Guam.

 

Going to Guam, d = v * 7 and returning d = (v + 4) * 5

 

Since the distance would be same, 7v = 5(v + 4) = 5v + 20

Solving this, 2v = 20 => v = 10 km/h, which is the ship's average outbound speed.