Ajay can row his boat in still water at a speed of 11 km/hr. If the speed of the stream is 7 km/hr, how long will it take to cover a distance of 54 km downstream?
Answer & explanation
Correct answer: option 4
Speed of boat in downstream = Speed of boat in still water + Speed of stream
= 11 + 7 = 18 km/hr
Time taken to cover 54 km downstream = $\frac{distance}{Speed\;downstream}$
= $\frac{54}{18}$ = 3 hours