Question

a motoboat whose speed in still WATER IN 18Km/h, takes 1 hour more to go 24 km upstream than to return downstream to the same spot. find the speed of the stream

 

Answer 1

Let speed of the stream in km/hr = x
And upstream speed of boat will be = 18 - x
similarly, speed of boat in downstream will be = 18  + x
Thus, time taken in upstream = 24 / (18 - x)
And , time losses in downstream = 24 / (18 + x)

As the question,  upstream time - downstream time = 1hr

$=>24/(18-x)-24/(18+x)=1$
$=>1/(18-x)-1/(18+x)=1/24$
$=>2x/(182-x2)=1/24$
$=>x2+48x-182=0$
$=>(x + 54)(x-6)=0$
$=> x = -54 (not possible)$
$=>x=6$

So the ans is speed of stream , x = 6 km/hr

Answer 2

answer is 6 km/hr .............