Question

Together two ferries can transport a day's cargo in 7 hours. The larger ferry can transport cargo three times faster than the smaller ferry. How long does it take the larger ferry to transport a day's cargo working alone?

Answer 1

9 hours, 20 minutes

Explanation:

When two ferries work together, they transport a day's cargo in 7 hours

The speed proportion or ratio of larger ferry to smaller ferry is given as 3 : 1

The sum of the ratio = 4 (3 + 1)

This means that it will take the smaller ferry = 7 x 4 hours to work alone = 28 hours, since the larger ferry is faster by 3.

Therefore, when larger ferry works alone, it will take it (7 x 4)/3 = 9.33 hours.

9.33 hours = 9 hours, 20 minutes.