Question

a man can row downstreme 20 km at 2hrs and upstreme 4 km at 2hrs find the speed of the boat in still water and speed of streme

Answer 1

Let the speed of the stream be x km/h

Let the speed of the boat in still water be y km/h

Downstream:

Speed = Distance ÷ Time

Speed = 20 ÷ 2 = 10 km/h

Upstream:

Speed = Distance ÷ time

Speed = 4 ÷ 2 = 2 km/h

Form equations:

y + x= 10 -------------- [ 1 ]

y - x = 2 -------------- [ 2 ]

[ 1 } + [ 2 ] :

2y = 12

y = 6 -------------- Sub into [ 2 ]

6 - x = 2

x = 4

Find the speeds of the boat in still water and speed of the stream:

speed of the stream =  x = 4 km/h

speed of the boat in still water =  y = 6 km/h

Answer: The speed of the stream is 4 km/h and the speed of the boat in still water is 6 km/h

Answer 2

The speed of stream is 4km/hr