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 businessman earns $28800 in December, thus decreasing his average annual (January to December) earnings by $1300. His average annual earnings would be
Source: CMAT Preparation

Option A: $29000

Option B: $33500

Option C: $40200

Option D: $41000

Option E: $43100
[EX A]: Option E

[EX Q]: Question: For any positive integer Y, the sum of the first Y positive integers equals Y(Y+1)/2 . If X and Y are positive integers and X > Y, what is the sum of all the integers between X and Y, inclusive?

Option A: X(X+1

Option B: X(X+1

Option C: X(X+1

Option D: X(X+1

Option E: X(Y+1
[EX A]: Option B

[EX Q]: Question: A man sells a car to his friend at 12% loss. If the friend sells it for Rs.54000 and gains 20%, the original C.P.of the car was :

Option A: Rs.21136.36

Option B: Rs.31136.36

Option C: Rs.51136.36

Option D: Rs.61136.36

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