a train 100 m long crosses a platform 125 m long in 30 sec ; find the speed of the train ?
"d = 100 + 125 = 225 t = 30 s = 225 / 30 * 18 / 5 = 27 kmph answer : c"
subtract(multiply(30, multiply(const_60.0, const_0_2778)), 100)