Pipes A, B can fill a tank in 15 minutes and 20 minutes respectively. But pipe C can empty the full tank in 12 minutes. If all these pipes are opened simultaneously, how much time will be taken to fill the tank?

• ক 30 minutes ✅ সঠিক উত্তর
• খ 38 minutes
• গ 29 minutes
• ঘ 35 minutes