Question

A man row with the stream for 10 minutes to cover 1 km. and goes 1km against the stream in 20 minutes? what was the speed of rowing?

Answer 1

speed for first 10minute

speed v1 =distance/time
=1÷10/60km/hour
=6km/hour

speed for second 20 minute
speed v2=1÷20/60
=3km /hour

therefore, average speed =v1+v2÷2
=6+3÷2
=4.5km/hour

Answer 2

Answer:

2kmph

Explanation:

x is man's speed. y is current speed.

Equation 1)

x+y=6kmph (1km in 10 min = 6kmph)

x-y=2kmph (1km in 30 min= 2kmph)

Add both equations

x+y+x-y = 6+2

2x = 8

X (man's speed) = 4 kmph

Y (current speed) = 2 kmph