A boat is moving 3 km against the current of the stream in 1 hour and moves 1 km in the direction of the current in 12 minutes. How long will it take the boat to go 6 km in stationary water?

The boat moves 3 km against the current in 1 hour.

The boat moves 1 km with the current in 12 minutes.

Downstream speed = Speed of boat + speed of current

Upstream speed = Speed of boat - speed of current

Time = $$\frac{\text{Distance}}{\text{Speed}}$$​​

Let B be the speed of the boat in still water (in km/h).

And let C be the speed of the current (in km/h).

Upstream Speed; B – C = 3 km/h ……..(i)

Downstream Speed: B + C = $$\frac{1}{0.2}$$ = 5km/h ……….(ii)

Adding the two equations:

(B + C) + (B - C) = 5 + 3

2B = 8

B = 4 km/h

Time taken to go 6 km by boat in still water,

$$\text{Time} = \frac{6}{4} = 1.5 \, \text{hours}$$​ = 1 hours 30 minute.

Thus, It will take the boat 1 hours 30 minute to go 6 km in stationary water.