Question

A boat running upstream takes 8 h 48 m to cover a certain distance, while it takes 4 h to cover the same distance running downstream. What is the ratio between the speed of the boat and the speed of the water current respectively?

Options

• 2 : 1

• 3 : 2

• 8 : 3

• Cannot be determined

Answer 1

8 : 3
Explanation:
Let the man's rate upstream be x km/h and that downstream by y km/h.
Then, distance covered upstream in 8 h 48 min
= Distance covered downstream in 4 h.

⇒ `(x xx8 4/5)=(yxx4)`

⇒ `44/5x=4y`

⇒ `y=11/5x`

∴ Required ratio = `((y+x)/2):((y-x)/2)`

= `((16x)/5xx1/2):((6x)/5xx1/2)`

= `8/5:3/5=8:3`