Beaten by a distance and a time — Aptitude Question
Beaten by a distance and a time: In a 200 m race A beats B by 20 metres or 5 seconds. What is A's time for the race? Answer and worked solution on CodeKairo.
- Topic: Time, Speed & Distance
- Section: Quantitative Aptitude
- Difficulty: Hard
- Time target: 120 seconds
Question
In a 200 m race A beats B by 20 metres or 5 seconds. What is A's time for the race?
Options
- 40 s
- 45 s
- 50 s
- 55 s
Show the answer and the worked solution
Correct answer: B. 45 s
Worked solution
- B covers 20 m in 5 s, so B's speed = 4 m/s.
- B's time for 200 m = 200 ÷ 4 = 50 s.
- A beats B by 5 s, so A takes 50 − 5 = 45 s.
Answer: 45 s.
The idea
'Beats by d metres or t seconds' means the loser needs t seconds to cover the last d metres. That gives the loser's speed, from which everything else follows.
Shortcut. The last 20 m is a tenth of the race and takes B 5 s, so B's full time is 10 × 5 = 50 s and A's is 5 s less: 45 s.
Common trap. 50 s — B's time for the race; A finishes 5 seconds sooner.