A man takes half time in rowing a certain distance downstream than upstream. What is the ratio of the speed in still water to the speed of current?
Answer & explanation
Answer: (d) 3: 1
Half the time over the same distance means the downstream speed is twice the upstream speed. So b + c = 2(b − c), which gives b = 3c: still-water speed : current = 3 : 1.
- Let the speed in still water be b and the current c.
- Downstream time is half the upstream time, so downstream speed = 2 × upstream speed.
- b + c = 2(b − c), so b = 3c.
- b : c = 3 : 1.
- Check: b = 3, c = 1 gives speeds 4 and 2 — half the time downstream.
Remember · Same distance: time ratio is the inverse of speed ratio. Downstream = b + c, upstream = b − c.
Question and answer: UPSC's official GS Paper II (2020, Series A) — paper ↗ · answer key ↗. Explanation: Minimalist IAS, checked 30 Sept 2026 (how we verify). ·