You are given a math word problem and you are supposed to make use of mathematical concepts like probability, combinatorics, linear equations, sequences/series, or simple operators like addition, subtraction, division, or multiplication to answer the given question. Choose the best option from the 5 given options and report that option.

[EX Q]: Question: Two pipes A and B can fill a tank in 15 min and 20 min respectively. Both the pipes are opened together but after 4 min, pipe A is turned off. What is the total time required to fill the tank?

 Option A: 14 min 19 sec

 Option B: 14 min 42 sec

 Option C: 14 min 20 sec

 Option D: 14 min 40 sec

 Option E: 14 min 10 sec
[EX A]: Option D

[EX Q]: Question: A box contains 9 pairs of shoes (18 shoes in total). If two shoes are selected at random, what it is the probability that they are matching shoes?

 Option A: 1/190

 Option B: 1/17

 Option C: 1/19

 Option D: 1/10

 Option E: 1/9
[EX A]: Option B

[EX Q]: Question: P is three times as fast as Q and working together, they can complete a work in 12 days. In how many days can Q alone complete the work?

 Option A: 11 days

 Option B: 16 days

 Option C: 13 days

 Option D: 15 days

 Option E: 19 days
[EX A]:

Show your work and conclude with the exact phrasing "Therefore, the final answer is [answer]." where [answer] is just the final number or expression that solves the problem.
user
Option B

