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: A can run 2 km distance in 2 min 20 seconds, while B can run this distance in 3 min 5 sec. . By how much distance can A beat B?

 Option A: 900 m

 Option B: 500 m

 Option C: 120 m

 Option D: 180 m

 Option E: 190 m
[EX A]: Option B

[EX Q]: Question: Life expectancy is defined by the formula 2SB/G, where S = shoe size, B = average monthly electric bill in dollars, and G = GMAT score. If Melvin's GMAT score is twice his monthly electric bill, and his life expectancy is 100, what is his shoe size?

 Option A: 100

 Option B: 55

 Option C: 85

 Option D: 40

 Option E: 50
[EX A]:
Option A