Question

The upstream speed of a boat is 18 km/hr which is 500% more than the speed of stream. find how much distance boat will cover in 3 hours while travelling in downstream.

Answer 1

Let the speed of the stream will be "v"

Now the upstream speed of the boat is 500% more than it

So upstream speed of the boat is 6 times of the speed of stream

now the upstream speed of boat is given as 18 km/h

now we have

$6v = 18$

$v = 3 km/h$

so speed of the stream will be 3 km/h

also since the upstream speed is given as

$v_{up} = v_b - v$

$18 = v_b - 3$

$v_b = 21 km/h$

now the downstream speed of boat is given as

$v_{down} = v_b + v = 21 + 3 = 24 km/h$

now the distance covered by the boat in downstream is given by

$d = v_{down}* t$

$d = 24*3 = 72 km$

so boat will cover 72 km in 3 hours