Three pipes A, B and C can fill a tank from empty to full in 30 minutes, 20 minutes and 10 minutes respectively. When the tank is empty, all the three pipes are opened. A, B and C discharge chemical solutions P, Q and R respectively. What is the proportion of solution P in the liquid in the tank after 3 minutes?
Choose the correct choice from the following answers.
A) 3/11 B) 2/11 C) 1/11 D) 4/11 E) 1/11
Part filled by (A + 2/11 + C) in 3 minutes = 3(1/30 + 1/20 + 1/10) = 11/20   Part filled by A in 3 minutes = 3/30   Required ratio = 3/30 * 20/11 = 2/11   Answer:2/11
<result>B</result>
Three pipes A, B and C can fill a tank from empty to full in 30 minutes, 20 minutes and 10 minutes respectively. When the tank is empty, all the three pipes are opened. A, B and C discharge chemical solutions P, Q and R respectively. What is the proportion of solution P in the liquid in the tank after 3 minutes?