walking at the rate of 3 kmph a man cover certain distance in 6 hr 40 min . running at a speed of 18 kmph the man will cover the same distance in .
"distance = speed * time 3 * 20 / 3 = 20 km new speed = 18 kmph therefore time = 20 / 18 = 10 / 9 = 54 min answer : c ."
multiply(divide(multiply(3, add(6, divide(40, const_60))), 18), const_60)