A motorboat goes 24 km in 2 hour along the stream and 10 km in 1 hour against the stream. The speed of the motorboat in kilometres per hour, is:

Solution (By Examveda Team)

$$\eqalign{ & {\text{B}} + {\text{W}} = 12{\text{ km/h}} \cr & {\text{B}} - {\text{W}} = 10{\text{ km/h}} \cr & \overline {\,{\text{B}} = \frac{{22}}{2} = 11{\text{ km/h}}\,} \cr} $$