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 P and Q can fill a cistern in 12 and 14 minutes respectively. Both are opened together, but at the end of 3 minutes the first is turned off. How much longer will the cistern take to fill?

 Option A: 11 1/2 min

 Option B: 11 1/4 min

 Option C: 11 2/4 min

 Option D: 11 1/5 min

 Option E: 10 1/2 min
[EX A]: Option E

[EX Q]: Question: A die is rolled twice. What is the probability of getting a sum equal to 9?

 Option A: 2/3

 Option B: 2/9

 Option C: 1/3

 Option D: 1/9

 Option E: 1/10
[EX A]: Option D

[EX Q]: Question: A boatman can row 3 km against the stream in 36 minutes and return in 18 minutes. Find the rate of current ?

 Option A: 7/2 kmph

 Option B: 2.5 kmph

 Option C: 5/2 kmph

 Option D: 1/2 kmph

 Option E: 2/2 kmph
[EX A]:
Option B