Q: Given a math problem with context and a question and 5 answer choices, the task is to provide the correct answer choice based on the problem. You must choose one of the given answer choices by letter: a, b, c, d, or e; anything else is invalid.
Problem: 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 ?
Options: a. 3 / 11, b. 2 / 11, c. 1 / 11, d. 4 / 11, e. 1 / 11
A:
b