a 300 m long train crosses a platform in 39 sec while it crosses a signal pole in 14 sec . what is the length of the platform ?
"speed = 300 / 14 = 150 / 7 m / sec . let the length of the platform be x meters . then , ( x + 300 ) / 39 = 150 / 7 = > x = 535.71 m . answer : d"
subtract(multiply(speed(300, 14), 39), 300)