two men started from the same place walk at the rate of 10 kmph and 12 kmph respectively . what time will they take to be 40 km apart , if they walk in the same direction ?
"to be 2 km apart they take 1 hour to be 10 km apart they take = 1 / 2 * 40 = 20 hours answer is d"
divide(subtract(12, 10), 40)