A motor boat takes 2 hours to travel a distance of 9 km downstream and it takes 6 hours to travel the same distance against the current. The speed of the boat in still water and that of the current (in km/h) respectively are:

Explanation:-

Downstream speed,
= ⁹/₂ = 4.5 kmph
Upstream speed,
= ⁹/₆ = 1.5 kmph
Thus, speed of boat in still water,
= ^{(4.5 +1.5)}/₂ = 3 kmph.
Speed of current = ^(4.5-1.5)/₂ = 1.5 km/h.