An express train travelled at an average speed of 100km/hr, stopping for 3 minutes after every 75km. How long did it take to reach its destination 600 km from the starting point?

A 6 hrs 21 min

B 6 hrs 24 min

C 6 hrs 27 min

D 6 hrs 30 min

Correct Answer: Option A

Normal time taken = 600/100 = 6 hr. stops = 600/75 – 1 = 8 – 1 = 7

subtracted 1 as at 600 km the last 8th stop. extra time = 7 × 3 = 21 minutes