2016 · Q18
When the speed of a train is increased by 20%, it takes 20 minutes less to cover the same distance. What is the time taken to cover the same distance with the original speed ?
Elementary MathematicsTime, Speed and Distance
- A140 minutes
- B120 minutes
- C100 minutes
- D80 minutes
Explanation
Let the original time be t minutes. Then v·t = 1.2v·(t−20), so t = 1.2t−24. This gives 0.2t = 24, hence t = 120 minutes (option B).