A boat covers 54 km distance in upstream in nine hours and the same boat covers 60 km distance in downstream in five hours. Find the ratio of speed of boat in still water to speed of stream.

Correct option is C

Let speed of boat in still water be x km/hr and speed of stream be y km/hr.
ATQ,
x – y = 54/9
x – y = 6 -----(i)
And,
x + y = 60/5
x + y = 12 -----(ii)
Form (i) and (ii) we get
2x = 18
x = 9
and y = 3
Required ratio = 9 : 3 = 3 : 1