Aman decided to cover a distance of 12 km in 78 minutes. He decided to cover the initial two-third of the distance at 10 km/h and the remaining at some different speed. Find the speed for the last one-third of the distance.
Show answer & explanation
Correct answer: B
Explanation
The correct answer is option 2 i.e. 8 km/h.
Total distance = 12 km
Time taken by Aman to cover two-third distance = 12 × (2/3)/10
⇒ 8/10 = 0.8 × 60 = 48 minutes
Remaining time = 78 - 48 = 30 minutes
Remaining distance = 12 - 8 = 4 km
Speed for the last one-third distance = 4/(30/60)
⇒ 4 × 2 = 8 km/h