X, Y and Z are three contestants in a race of 1000 m. Assume that all run with different uniform speeds. X gives Y a start of 40 m and X gives Z a start of 64 m. If Y and Z were to compete in a race of 1000 m, how many metres start will Y give to Z?
Answer & explanation
Answer: (b) 25
While X runs 1000 m, Y runs 960 m and Z 936 m. So while Y runs 1000 m, Z runs 1000 × 936/960 = 975 m, and Y can give Z a start of 25 m.
- X gives Y 40 m: while X runs 1000 m, Y runs 960 m.
- X gives Z 64 m: in the same time Z runs 936 m.
- Speed ratio Y : Z = 960 : 936.
- While Y runs 1000 m, Z runs 1000 × 936/960 = 975 m.
- Start Y gives Z = 1000 − 975 = 25 m.
Remember · Turn 'starts' into distances run in the same time, then scale to the new race length.
Question and answer: UPSC's official GS Paper II (2019, Series A) — paper ↗ · answer key ↗. Explanation: Minimalist IAS, checked 30 Sept 2026 (how we verify). ·