a 1200 m long train crosses a tree in 120 sec , how much time will i take to pass a platform 800 m long ?
"l = s * t s = 1200 / 120 s = 10 m / sec . total length ( d ) = 2000 m t = d / s t = 2000 / 10 t = 200 sec answer : b"
divide(add(1200, 800), divide(1200, 120))