a 1500 m long train crosses a tree in 120 sec , how much time will it take to pass a platform 500 m long ?
"l = s * t s = 1500 / 120 s = 12.5 m / sec . total length ( d ) = 2000 m t = d / s t = 2000 / 12.5 t = 160 sec answer : b"
divide(add(1500, 500), divide(1500, 120))