Question

A boat travels to an island and back in 78 minutes. If the speed of the boat going to the island is 14 mph, and its speed returning is 12 mph, how far away is the island

Answer 1

8.4 miles

Explanation:

Given that :

Total time taken = 78 minutes = 78/60 = 1.3 hours

To Speed = 14 mph

Fro Speed = 12 mph

Let the distance be represented as, d

Distance = speed * time

Time = distance / speed

To time + Fro time = 1.3 hours

d / 14 + d / 12 = 1.3 hours

Take lcm of 14 and 12 ; = 84

(6d + 7d) / 84 = 1.3

13d /84 = 1.3

13d = 1.3 * 84

13d = 109.2

d = 109.2 / 13

d = 8.4 miles

The distance is 8.4 miles