Multiple choice

A train starts moving at the speed of 60 kmph with its speed increasing every 3 hours by 8.5 kmph. In how many hours will the train cover 920 km?

  1. 10 hours

  2. 12.5 hours

  3. 13 hours

  4. 14.5 hours

  5. 15 hours

Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Speed increases every 3 hours. 0-3h: 60 kmph (dist 180). 3-6h: 68.5 kmph (dist 205.5). 6-9h: 77 kmph (dist 231). 9-12h: 85.5 kmph (dist 256.5). Total dist = 180 + 205.5 + 231 + 256.5 = 873. Remaining dist = 920 - 873 = 47. Next speed = 94 kmph. Time = 47 / 94 = 0.5 hours. Total time = 12 + 0.5 = 12.5 hours.