Boats and Streams - General Aptitude

Q1:

A boat running upstream takes 8 hours 48 minutes to cover a certain distance, while it takes 4 hours to cover the same distance running downstream. What is the ratio between the speed of the boat and speed of the water current respectively?

A 2 : 1

B 3 : 2

C 8 : 3

D Cannot be determined

E None of these

ANS:C - 8 : 3

Let the man's rate upstream be x kmph and that downstream be y kmph. Then, distance covered upstream in 8 hrs 48 min = Distance covered downstream in 4 hrs.

x x 8 4 = (y x 4)
5
44 x =4y
5
 y = 11 x.
5
 Required ratio = y + x : y - x
2 2
   = 16x x 1 : 6x x 1
5 2 5 2
   = 8 : 3
5 5
   = 8 : 3.