The total time taken by a boat to cover 30 km upstream and X km downstream in 13 hours. If the speed of the stream is 3 km/hr and the speed of the boat in still water is twice the speed of the stream, then find ‘X’ is what percent of 180.

Correct option is C

Given, Speed of stream=3 km/hr
So, speed of boat in still water=2×3=6 km/hr
ATQ,
30/(6-3) + X/(6+3) = 13
10+X/9 = 13
X=3×9
X=27
Required percent=27/180 × 100 = 15%