Question

A steamer moves with a speed of 4.5 km/h in still water to a certain upstream point and comes back to the starting point in a river which flows at 1.5 km/h. The average speed of steamer for the total journey is (a) 12

Answer 1

Dear Student,

◆ Answer -

vavg = 4 km/h

● Explaination -

Upstream speed of the streamer is -

vu = 4.5 - 1.5

vu = 3 km/h

Downstream speed of the steamer is -

vd = 4.5 + 1.5

vd = 6 km/h

Let x be distance to travel.

vavg = (x + x) / (x/vu + x/vd)

vavg = 2x / (x/3 + x/6)

vavg = 2x / (3x/6)

vavg = 4 km/h

Therefore, average speed of steamer for the total journey is 4 km/h.

Thanks dear...