a train speeds past a pole in 25 seconds and a platform 200 m long in 30 seconds . its length is :
"let the length of the train be x meters and its speed be y m / sec . they , x / y = 25 = > y = x / 25 x + 200 / 30 = x / 25 x = 1000 m . answer : option d"
multiply(200, subtract(const_2, const_1))