Question

The speed of a stream is 3 km/hr. A boat goes 24 km and comes back to the starting point in 6 hours. What is the speed (in km/hr) of the boat in still water?

विकल्प

• 4

• 9

• 8

• 12

Answer 1

9

Explanation:

`24/(x + 3) + 24/(x - 3)` = 6

Put your options to solve for `x`

`24 [(x - 3 + x + 3)/(x^2 - 9)]` = 6

⇒ `8x = x^2 - 9`

⇒ `x^2 - 8x - 9` = 0

⇒ `x` = 9, – 1

This is not possible.