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:

Answer: Option B

Downstream speed,
= $$\frac{9}{2}$$ = 4.5 kmph
Upstream speed,
= $$\frac{9}{6}$$ = 1.5 kmph
Thus, speed of boat in still water,
= $$\frac{4.5+1.5}{2}$$   = 3 km/h
Speed of current = $$\frac{4.5-1.5}{2}$$   = 1.5 km/h