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
"length of train = 12 ã — 15 = 180 m . then , speed of train = 180 â  „ 9 = 20 m / s now , length of train = 11 ã — 15 = 165 m â ˆ ´ required time = 165 â  „ 20 = 8.25 sec . answer d"
divide(subtract(multiply(12, 15), 15), divide(multiply(12, 15), 9))