Answer: The outbound trip is 18 miles per hour
Explanation:
Let x represent the speed of the plane.
An aircraft carrier made a trip. Let us assume that this trip was outbound. The trip there took 5 hours.
Distance = speed × time. Therefore
Distance = 5x
The trip back took 6 hours. It averaged 3 mph faster on the trip there then on the return trip. This means that the speed on the trip back is x - 3 mph.
Distance = 6(x-3) = 6x - 18
Since the distance is the same,
5x = 6x - 18
6x - 5x = 18
x = 18
The speed on return or inbound trip would be 18 - 3 = 15 mph