In a river flowing at 2 km/hr, a boat travels 32 km upstream and then returns downstream to the starting point. If its speed in still water be 6 km/hr, find the total journey time.
10 hours
12 hours
14 hours
16 hours
Explanation:
speed of the boat = 6 km/hr
Speed downstream = (6+2) = 8 km/hr
Speed upstream = (6-2) = 4 km/hr
Distance travelled downstream = Distance travelled upstream = 32 km
Total time taken = Time taken downstream + Time taken upstream
$= \dfrac{32}{8} + \dfrac{32}{4} = \dfrac{32}{8} + \dfrac{64}{8} = \dfrac{96}{8}$ = 12 hr