Subject: General Aptitude · Chapter: Boats and Streams · Exam: 2006 · Marks: · Difficulty:
A boat takes half time in moving a certain distance downstream than upstream. What is the ratio between the rate in still water and the rate of current?
(a)1 : 2
(b)2 : 1
(c)1 : 3
(d)3 : 1
Answer
Answer (as printed): D
Explanation
Ratio of times taken (Downstream : Upstream) = 1 : 2. ∴ Speed downstream : Speed upstream = 2 : 1. Let speed downstream $=2 x \mathrm{kmph}$ and speed upstream $=x \mathrm{kmph}$. Required ratio $=\frac{\text { Rate in still water }}{\text { Rate of current }}=\frac{\frac{1}{2}(2 x+x)}{\frac{1}{2}(2 x-x)}=3: 1$.
Explanation as extracted from the printed page; notation may be imperfect.