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: The purchase price of an article is $48. In order to include 5% of cost for overhead and to provide $12 of net profit, the markup should be

 Option A: 15%

 Option B: 25%

 Option C: 30%

 Option D: 40%

 Option E: 45%
[EX A]: Option C

[EX Q]: Question: If integers a and b are distinct factors of 30, which of the following CANNOT be a factor of 30?
I. ab + b^2
II. (a + b)^2
III. a + b

 Option A: I only

 Option B: II only

 Option C: III only

 Option D: I and II only

 Option E: I, II, and III
[EX A]: Option B

[EX Q]: Question: A man sells a horse for Rs. 620 and loses something, if he had sold it for Rs.860 , his gain would have been double the former loss. Find the cost price of the horse?

 Option A: 27

 Option B: 98

 Option C: 27

 Option D: 80

 Option E: 71
[EX A]:
Option D