A tank is filled by two pipes, where the faster pipe fills it three times quicker than the slower one. If both pipes working together fill the tank in 36 minutes, how long will it take the slower pipe alone to fill the tank?

Explanation

Let the slower pipe fill the tank in x minutes. Then the faster pipe fills it in x/3 minutes. Their combined rate is 1/36 tanks per minute. The sum of their rates is 1/x + 3/x = 4/x = 1/36, so x = 144 minutes. Therefore, the slower pipe alone takes 144 minutes to fill the tank.