a 300 m long train crosses a platform in 39 sec while it crosses a signal pole in 10 sec . what is the length of the platform ?
"speed = 300 / 10 = 30 m / sec . let the length of the platform be x meters . then , ( x + 300 ) / 39 = 30 = > x = 870 m . answer : e"
subtract(multiply(speed(300, 10), 39), 300)