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 a committee of 2 people is to be selected from among 5 married couples so that the committee does not include two people who are married to each other, how many such committees are possible?

 Option A: 20

 Option B: 40

 Option C: 50

 Option D: 80

 Option E: 120
[EX A]: Option B

[EX Q]: Question: A broker invested her own money in the stock market. During the first year, she increased her stock market wealth by 40 percent. In the second year, largely as a result of a slump in the stock market, she suffered a 30 percent decrease in the value of her stock investments. What was the net increase or decrease on her overall stock investment wealth by the end of the second year?

 Option A: −5%

 Option B: −2%

 Option C: 15%

 Option D: 20%

 Option E: 80%
[EX A]: Option B

[EX Q]: Question: If e 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: y/z
[EX A]:
Option E