A train consists of 12 boggies, each boggy 15 metres long. The train crosses a telegraph post in 9 seconds. Due to some problem, one boggies were detached. The train now crosses a telegraph post in  Choose the correct choice from the following
A) 18 sec  B) 12 sec  C) 15 sec  D) 8.25 sec  E) None of these
Length of train = 12 Ã— 15 = 180 m.   Then, speed of train = 180â„9 = 20 m/s   Now, length of train = 11 Ã— 15 = 165m   âˆ´ Required time = 165â„20 = 8.25 sec.   Answer 8.25 sec
<result>D</result>
A train consists of 12 boggies, each boggy 15 metres long. The train crosses a telegraph post in 9 seconds. Due to some problem, one boggies were detached. The train now crosses a telegraph post in