A train consists of 12 boggies, each boggy 15 metres long. The train crosses a telegraph post in 9 seconds. Due to some problem, two boggies were detached. The train now crosses a telegraph post in Choose the correct choice from the following choices.
A) 18 sec B) 7.5 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 = 10 Ã— 15 = 150m   âˆ´ Required time = 150â„20 = 7.5 sec.   Answer 7.5 sec
<result>B</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, two boggies were detached. The train now crosses a telegraph post in