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: A is faster than B. A and B each walk 24 km. The sum of their speeds is 7 km/hr and the sum of times taken by them is 14 hours. Then, A's speed is equal to?

 Option A: 2 km/hr

 Option B: 3 km/hr

 Option C: 4 km/hr

 Option D: 7 km/hr

 Option E: 8 km/hr
[EX A]: Option B

[EX Q]: Question: If x, y, and z are negative integers and 3x - 3y = -3z, then which of the following statements must be true?
I. x > y
II. x > y > z
III. x = z

 Option A: I and II

 Option B: I only

 Option C: II only

 Option D: III only

 Option E: None
[EX A]: Option B

[EX Q]: Question: The average earning of a mechanic for the first-four days of a week is Rs. 18 and for the last four days is Rs. 22. If he earns Rs . 34 on the fourth day, his average earning for the whole week is ?

 Option A: Rs . 15.95

 Option B: Rs 16

 Option C: Rs. 18

 Option D: Rs. 25.71

 Option E: None of these
[EX A]:
Option C