Question

A boat goes from point A to B downstream of a river flowing with speed 6km/h and then comes back to point A. If time taken in upstream journey is double of that in downstream journey then speed of boat in still water is? ​

Answer 1

Hii there,

◆ Answer -

Speed of boat in still water = 4.5 km/h

● Explanation -

Let vb & vr be speed of boat and riverstream respectively.

Time taken by boat to travel downstream is given by -

t = s / (vb + vr)

t = s / 6

Time taken by boat to travel upstream is given by -

t' = s / (vb - vr)

Given that t' = 2t.

t' = 2t

s / (vb - vr) = 2 × s / 6

vb - vr = 3

Now we have two equations -

vb + vr = 6 km/h

vb - vr = 3 km/h

Solving these two equations -

vb = 4.5 km/h

vr = 1.5 km/h

Therefore, speed of boat in still water will be 4.5 km/h.

Thanks dear...

Answer 2

Answer: here's the answer

Explanation: