Question

A boat covers a distance of 60 km in the direction of flow of water in 4 hours. If the speed of boat in still water is double the speed of flow of water, then how much distance will it cover in 2 hours opposite the flow?

Answer 1

Answer:

10 km

Step-by-step explanation:

We will take speed of flow of water as y and speed of boat in still water as x.

Therefore, when the boat moves with the flow of the water, the speed of the boat becomes (x+y). Similarly, when it moves against the flow of the water, the speed is (x-y).

Now, according to the question, the boat covers a distance of 60 km in the direction of flow of water in 4 hours, so (x+y)=60/4 {since speed=distance/time}.

Now, it is also said that x=2y. Therefore, we can substitute this into the above equation.

Now, 2y+y=60/4

3y=15

y=5

Putting y in our first equation,

x+5=15

x=10

Now, we have to find the distance it travels in 2 hrs opposite the flow, so, speed of the boat will be (x-y)=10-5=5km/h.

distance = speed * time

distance=5km/h * 2h

distance=10km

Hope you understood!