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: If x persons take y days to complete z similar jobs, how long does it take y persons to complete 1 such job?

 Option A: z

 Option B: x

 Option C: x/y

 Option D: z/x

 Option E: x/z
[EX A]: Option E

[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]: Option B

[EX Q]: Question: What profit percent is made by selling an article at a certain price, if by selling at 1/2rd of that price, there would be a loss of 20%?

 Option A: 20%

 Option B: 29%

 Option C: 60%

 Option D: 27%

 Option E: 28%
[EX A]:
Option C