a train of length 250 m crosses a bridge of length 180 m in 20 seconds . what is the speed of train ?
"sol : ( length of train + length of bridge ) = speed of train x time ( 250 + 180 ) = 20 x speed speed = 430 / 20 = 21.5 m / s = 77.4 km / h answer = b"
multiply(const_3_6, divide(add(250, 180), 20))