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.
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Question: Question: One water pump can fill half of a certain empty tank in 7 hours. Another pump can fill half of the same tank in 7.5 hours. Working together, how long will it take these two pumps to fill the entire tank?

 Option A: 7 7/13

 Option B: 1 5/8

 Option C: 3 1/4

 Option D: 7 7/29

 Option E: 3 1/2

Answer: Option D


Question: Question: The difference between the place values of 7 and 3 in the number 527435 is

 Option A: 4

 Option B: 5

 Option C: 45

 Option D: 6970

 Option E: None

Answer: Option D


Question: Question: If (x + 1) times (4x + 1) is an odd integer, then x must be:

 Option A: an odd integer

 Option B: an even integer

 Option C: a prime number

 Option D: a composite number

 Option E: a negative integer

Answer:
Option B