Question

A boat moves downstream at the rate of 12 km/
hr and upstream at 4 km/hr. Find the speed of
the boat in still water and also the speed of current. 7.
(1) 7 km/hr, 2 km/hr
(2) 6 km/hr. 2 km/hr
(3) 7 km/hr, 1 km/hr
(4) 7.5 km/hr, 1.5 km/hr
(5) None of these
7
What is the answer ​

Answer 1

Answer is in the picture.

Answer 2

Option(5) None of these is the correct answer.

Given,

The downstream speed = 12 km/hr

The upstream speed = 4 km/hr

To Find,

The speed of the boat in still water =?

The speed of the current =?

Solution,

From the formula of the speed of the current, we have

The speed of current = (Downstream speed - Upstream speed) / 2

The speed of current = (12 - 4) / 2

The speed of current = 8 / 2

The speed of current  = 4 km/hr

We also know that,

The downstream speed  = The speed of current + The speed of a boat in still water

12 = 4 + The speed of a boat in still water

The speed of a boat in still water = 12 - 4

The speed of a boat in still water = 8 km/hr

Hence, the speed of the boat in still water is 8km/hr and the speed of the current is 4km/hr. The answer is 8km/hr, 4 km/hr.