Two pipes P and Q can fill a cistern in 12 minutes and 16 minutes respectively. Simultaneously both the pipes are opened together, then after how much time Q should be closed so that the tank is full in 9 min ? February 25, 2021 / By Preparation Point / Basic Maths Mcqs Share on WhatsApp Share on Facebook Share on Twitter Share on LinkedInA. 2 min B. 3 min C. 4 min D. 5 min Share this:TwitterFacebookMoreTelegramWhatsAppLike this:Like Loading... Related Share on WhatsApp Share on Facebook Share on Twitter Share on LinkedIn