An express train travelled at an average speed of 100 km / hr, stopg for 3 minutes after every 75 km. 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
Time taken to cover 600 km = ( 600/100 ) hrs = 6 hrs. Number of stoppages = ( 600/75 – 1 ) = 7 Total time of stoppage = (3 x 7) min = 21 min. Hence, total time taken = 6 hrs 21 min.