two pipes a and b can fill a tank in 24 hours and 36 hours respectively . if both the pipes are opened simultaneously , how much time will be taken to fill the tank ?
"part filled by a in 1 hour = 1 / 24 part filled by b in 1 hour = 1 / 36 part filled by ( a + b ) in 1 hour = 1 / 24 + 1 / 36 = 5 / 72 both the pipes together fill the tank in 72 / 5 = 14 2 / 5 hours answer is c"
divide(const_1, add(divide(const_1, 24), divide(const_1, 36)))