Question

A ship traveling east at 45 mph is 15 mi from a harbor when another ship leaves the harbor traveling east at 60 mph. How long does it take the second ship to catch up to the first ship?

Answer 1

1 hour

Explanation:

I find these easiest to work by considering the initial difference in distance and the speed at with that gap is closing.

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The gap is 15 miles, the distance the first ship is from harbor when the second ship starts.

The rate of closure is the difference in the speeds of the two ships:

60 mph -45 mph = 15 mph

Then the closure time is ...

time = distance/speed

time = (15 mi)/(15 mi/h) = 1 h

It will take the second ship 1 hour to catch up to the first ship.