Question

A man goes upstream for a distance of 10 km in 5 hrs. another man goes downstream the same distance of 10 km in 3 hrs. what is the difference in speed of 2 men if the river speed is 0.5 kmph?

Answer 1

speed of a man who goes upstream
= 2-0.5 =1.5
speed of another man who goes downstream
=3.3+0.5 = 3.8
difference of their speed = 3.8 -1.5 =2.3

Answer 2

The speed difference of downstream and upstream is 0.33 kmph.

Solution:

The speed of the river as given in the question as 0.5 kmph

The speed of main going upstream $=\frac{10}{5}$ = 2 kmph.

The speed of man swimming downstream $=\frac{10}{3}$ = 3.33 kmph.

The real speed of man going upstream = (speed of man upstream + speed of the river) = 2 + 0.5 = 2.5 kmph.

The real speed of the man going downstream = (speed of the man downstream - speed of the river) = 3.33 - 0.5 = 2.83 kmph.

The speed difference of downstream and upstream = 2.83 - 2.5  

= 0.33 kmph.

Therefore, the speed difference of 2 men is 1.33 kmph.