Question

A submarine let Hawaii two hours before an aircraft carrier. The vessels traveled in opposite directions. The aircraft carrier traveled at 25 mph for nine hours. After this time the vessels were 280 miles apart. Find the submarines speed.

Answer 1

Answer: the speed of the submarine is 5miles per hour

Step-by-step explanation:

The submarine left Hawaii two hours before the aircraft carrier.

Let x = the speed of the submarine

The aircraft carrier traveled at 25 mph for nine hours.

After this time the vessels were 280 miles apart. This means that when they became 280 miles apart, the aircraft carrier has travelled for 9 hours. If the submarine was ahead of the aircraft carrier with 2 hours, that means that the submarine travelled 9 + 2 = 11 hours

Distance travelled = speed × time

Distance travelled by submarine will be 11 × x = 11x miles per hour

Distance travelled by aircraft carrier will be 25 × 9 = 225 miles per hour

If they are 280 miles apart, this would be their total distance. Therefore,

225 + 11x = 280

11x = 280 - 225 = 55

x = 55/11 = 5miles per hour