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 Q in the liquid in the tank after 3 minutes?
Options:
(A) 1/11
(B) 2/11
(C) 3/11
(D) 4/11
(E) 5/11 Now, let's think a bit. Some random thoughts:
Part filled by (A + B + C) in 3 minutes = 3(1/30 + 1/20 + 1/10) = 11/20
Part filled by B in 3 minutes = 3/20
Required ratio = 3/20 * 20/11 = 3/11
The final answer: (C).