Answer:
The speed of the submarine is 5 mph
Step-by-step explanation:
Let x represent the speed of the submarine.
A submarine left Hawai'i 2 hours before an aircraft carrier. If the aircraft carrier travelled for 9 hours and after this time, the vessels were 280 miles apart, it means that submarine travelled for 9 + 2 = 11 hours and the total distance covered by submarine and the aircraft is 280 miles.
Distance = speed × time
Distance covered by the submarine would be
11 × x = 11x
The aircraft carrier traveled at 25 mph. Distance covered by the aircraft would be
25 × 9 = 225
Therefore,
225 + 11x = 280
11x = 280 - 225 = 55
x = 55/11 = 5mph
