A boat goes 24 km upstream and 28 km downstream in 6 hours. It goes 30km upstream and 21km downtream in 6.5 hours. Find the speed of the boat in the still water and the speed of stream.
Let speed of boat be x kmph and of the stream be y kmph
When boat goes upstream, effective speed of boat will be x - y and when boat goes downstream, its speed will be x+y.
Case 1 :
To travel 24 km upstream, it takes 24/(x-y) hrs
To travel 28 km downstream, it takes 28 / ( x + y ) hrs
24/(x-y) + 28 / ( x + y ) = 6 - - - ( 1 )
Similarly for case 2, we get
30/(x-y) + 21 / ( x + y ) = 6.5 - - - ( 2)
Solve equations 1 and 2