A pipe can fill up an empty tank in 12 minutes, Another pipe flows out 8 liters of water per minute. If the two pipes are opened together and the empty tank is filled up in 84 minute. How much water does the tank contain?

Question: A pipe can fill up an empty tank in 12 minutes, Another pipe flows out 8 liters of water per minute. If the two pipes are opened together and the empty tank is filled up in 84 minutes. How much water does the tank contain? Solution:Let the tank empty in x minuteAccording to the question, (1/12) - (1/x) = 1/84⇒ (1/12) - (1/84) = 1/x⇒ 6/84 = 1/x⇒ x = 84/6 ⇒ x = 14 The tank emptied by the other pipe in 14 minute∴ The tank contain = 14 × 8 = 112 liter