Question

The speed of a boat in still water is 18 km/h and the speed of the current is 6 km/h. In how much time (in hours) will the boat travel a distance of 90 km upstream and the same distance downstream?

Options

• `9 1/2`

• `11 1/4`

• 12

• 10

Answer 1

`11 1/4`

Explanation:

`90/(18 - 6) + 90/(18 + 6) = 90/12 + 90/24`

= (7 h 30 m) + (3 h 45 m)

= `11 1/4` h