Question

A 10 foot rope ladder hangs over the side of a boat with the bottom rung on the surface of the water. The rungs are one foot apart, and the tide goes up at the rate of 6 inches per hour. How long will it be until three rungs are covered?

Answer 1

6 inches per hour = 12 per 2 hour
= 1 foot per 2 hour
To cover 3 rungs, 3 feet are to be covered.
If 1 foot is 2hr,
then 3 feet is 6 hr
Therefore the answer is 6 hour.