Let x be the speed of the boat in still water and y be the speed of the current of the river. The downstream speed will be x+y, the upstream speed will be x-y. but: distance=speed*time therefore; as the boat travels in 2 hours downstream we shall have: 2(x+y)=48......i and as the boat travels upstream we shall have: 3(x-y)=48........ii simplifying i and ii we get: x+y=24....iii x-y=16....iv adding the above iii and iv we get 2x=40 x=40/2=20 substituting x=20 into iii we obtain: 20+y=24 y=24-20 y=4 so the speed of the boat in still waters is 20 miles per hour the rate of the stream is 4 miles per hour
