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.

[Q]: Question: If x, y, and z are positive integers such that x is a factor of y and y is a factor of z, which of the following is NOT necessarily an integer?

 Option A: (x + y

 Option B: (y + z

 Option C: yz/x

 Option D: (2y + 3z

 Option E: (xy + z
[A]: Option A


[Q]: Question: In 165 litres of mixtures of milk and water, water is only 28%. The milkman sold 40 litres of this mixture and then he added 30 litres of pure milk and 13 litres of pure water in the remaining mixture. What is the percentage of water in the final mixture?

 Option A: 29.35%

 Option B: 28. 57%

 Option C: 24. 57%

 Option D: 27. 75%

 Option E: 26. 57%
[A]: Option B


[Q]: Question: A, B and C can do a piece of work in 24, 30 and 40 days respectively. They start the work together but C leaves 4 days before the completion of the work. In how many days is the work done?

 Option A: 15 days

 Option B: 14 days

 Option C: 13 days

 Option D: 11 days

 Option E: 10 days
[A]:
Option D