Let the speed of the stream be x km/hr
Therefore the speed of of boat upstream is 24-x km/hr
and speed of the boat downstream is 24-x km/hr.

time= distance/speed

32/(24-x)  - 32/ (24+x)  = 1

Solve this and you'll get the speed.

Total Distance = 32km
Speed in Still Water = 24km/hr
Let the speed of stream be 'x' kmph
then, Speed moving upstream = 24-x
         Speed moving downstream = 24+x
We know that \frac{Distance}{Speed} \frac  is time 
</span>{32}{24-x} - \frac{32}{24+x} = 1
On reducing it to a quadratic equation,
we get -  x^{2} + 64x-576=0
On solving it by splitting the middle term method (8&72 as factors) we get,
x = 8 or -72
Since, the speed cannot be negative, x = 8
Therefore, the speed of the stream is 8 km/hr
Sorry, there is a mistake after </span> text, its actually -> 32/(24-x) - 32/(24+x) = 1