Question 75

The speed of a boat in still water is 15 km/h. The speed of the current is 3 km/h. In how much time(in hours) will the boat travel a distance of 54 km upstream and the same distance downstream?

Solution

Given, speed of boat = 15 km/hr , speed of current = 3 km/hr

In Upstream = Speed of boat - speed of current

i.e 15 - 3 = 12 km/hr

In Downstream = Speed of boat + speed of current

i.e 15 + 3 = 18 km/hr

According to question,

Required time to travel of distance of 54 km upstream and 54 km downstream

T = $$\frac{54}{12}+\frac{54}{18}=4.5\ +3$$

i.e, 7.5 hrs

Hence, Option A is correct.

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