A train consists of 12 boggies, each boggy 15 metres long. The train crosses a telegraph post in 9 seconds. Due to some problem, three boggies were detached. The train now crosses a telegraph post in Choose the correct choice from the following:
A) 6.75 sec
B) 12 sec
C) 15 sec
D) 20 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 = 9Ã— 15 = 135m   âˆ´ Required time = 135â„20 = 6.75 sec.   6.75 secnswer 6.75 sec
<result>A</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, three boggies were detached. The train now crosses a telegraph post in