The speed of a boat in still water is 15 km/h, and the speed of the current is 5 km/h. In how much time (in hours) will the boat travel a distance of 60 km upstream and the same distance downstream?
A. 10 hr
B. 9 hr
C. 20 hr
D. 12 hr
Answer: Option B
Solution (By Examveda Team)
Speed of boat in still water = 15 km/hrSpeed of stream = 5 km/hr
Total time of upstream and downstream
$$\eqalign{ & = \frac{{60}}{{15 - 5}} + \frac{{60}}{{15 + 5}} \cr & = 6 + 3 \cr & = 9{\text{ hr}} \cr} $$
This Question Belongs to Arithmetic Ability >> Boats And Streams
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