a 300 m long train crosses a platform in 39 sec while it crosses a signal pole in 8 sec . what is the length of the platform ?
"speed = 300 / 8 = 75 / 2 m / sec . let the length of the platform be x meters . then , ( x + 300 ) / 39 = 75 / 2 = > x = 1162.5 m . answer : e"
subtract(multiply(speed(300, 8), 39), 300)