A motor boat whose speed is 24 km/h in still water takes 1 hour more to go 32 km upstream than to return downstream to the same spot. Find the speed of the stream.

Let the speed of the stream be x km/hr
Speed of the boat in still water = 24 km/hr
Speed of the boat in upstream = (24-x) km/hr
Speed of the boat in downstream = (24+x) km/hr
Distance between the places is 32 km.
Time to travel in upstream = d/(24-x) hr
Time to travel in downstream = d/(24+x) hr
Difference between timings = 1 hr
Time of upstream journey = Time of downstream journey + 1 hr
Therefore, 32/(24-x) = 32/(24+x) + 1
32/(24-x) - 32/(24+x) = 1
32(24+x) - 32(24-x) = (24-x)(24+x)
768 + 32x - 768 + 32x = 576 - x²
x² + 64x - 576 = 0
On factoring, we get (x+72)(x-8) = 0
So, x = 0 or 8 (speed of the stream cannot be negative)
Therefore, speed of stream is 8 km/hr.