Two pipes P and Q can fill a cistern in 12 min. and 15 min. respectively but a third pipe ‘R’ can empty the full tank in 6 min. P and Q are kept open for 5 min. in the beginning and then ‘R’ is also opened. In what time is the cistern emptied ? February 25, 2021 / By Preparation Point / Basic Maths Mcqs Share on WhatsApp Share on Facebook Share on Twitter Share on LinkedInA. 30 min B. 35 min C. 40 min D. 45 min Share this:TwitterFacebookMoreTelegramWhatsAppLike this:Like Loading... Related Share on WhatsApp Share on Facebook Share on Twitter Share on LinkedIn