Stoppages on a bus route — Aptitude Question
Stoppages on a bus route: A bus without stoppages averages 54 km/h, and with stoppages 45 km/h. Answer and worked solution on CodeKairo.
- Topic: Time, Speed & Distance
- Section: Quantitative Aptitude
- Difficulty: Medium
- Time target: 90 seconds
Question
A bus without stoppages averages 54 km/h, and with stoppages 45 km/h. For how many minutes per hour does the bus stop?
Options
- 8 min
- 10 min
- 12 min
- 15 min
Show the answer and the worked solution
Correct answer: B. 10 min
Worked solution
- Distance lost per hour = 54 − 45 = 9 km.
- Time to cover 9 km at the running speed = 9/54 h = 1/6 h.
- That is 10 minutes per hour.
Answer: 10 min.
The idea
Stoppage time per hour = (difference in speeds) ÷ (speed without stoppages), expressed in minutes. The running speed is always the divisor.
Shortcut. The bus moves for only 45/54 = 5/6 of each hour, so it stands still for 1/6 of an hour — 10 minutes.
Common trap. 12 min — dividing the 9 km lost by 45, the speed with stoppages (9/45 h = 12 min); the lost distance is made up at the running speed of 54.