two trains each 250 m in length are running on the same parallel lines in opposite directions with the speed of 80 kmph and 70 kmph respectively . in what time will they cross each other completely ?
"d = 250 m + 250 m = 500 m rs = 80 + 70 = 150 * 5 / 18 = 125 / 3 t = 500 * 3 / 125 = 12 sec answer : c"
divide(250, multiply(80, const_0_2778))