Opposite directions on a track — Aptitude Question
Opposite directions on a track: Two runners start together on a 600 m circular track in opposite directions at 4… Answer and worked solution on CodeKairo.
- Topic: Time, Speed & Distance
- Section: Quantitative Aptitude
- Difficulty: Medium
- Time target: 60 seconds
Question
Two runners start together on a 600 m circular track in opposite directions at 4 m/s and 6 m/s. After how long do they first meet?
Options
- 50 s
- 60 s
- 75 s
- 100 s
Show the answer and the worked solution
Correct answer: B. 60 s
Worked solution
- Closing speed = 4 + 6 = 10 m/s.
- Together they must cover one lap of 600 m.
- Time = 600 ÷ 10 = 60 s.
Answer: 60 s.
The idea
Opposite directions close the lap at the sum of the speeds. Note they meet somewhere on the track, not at the starting point.
Shortcut. Together they cover 10 m of track a second, so the 600 m lap closes in 60 s; check: 240 m + 360 m = 600 m.
Common trap. 100 s — the faster runner's own lap time (600 ÷ 6), as if they could meet only back at the start; running towards each other they meet part-way round.