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: P alone can complete a piece of work in 14 days. Work done by Q alone in one day is equal to one-third of the work done by P alone in one day. In how many days can the work be completed if P and Q work together?

 Option A: 6 (1/4

 Option B: 21/2 days

 Option C: 7 (3/4

 Option D: 8/5 days

 Option E: 9 (3/4
[EX A]: Option B

[EX Q]: Question: A reduction of 25% in the price of oil enables a house wife to obtain 5kgs more for Rs.800, what is the reduced price for kg?

 Option A: 72

 Option B: 27

 Option C: 40

 Option D: 28

 Option E: 20
[EX A]: Option C

[EX Q]: Question: The average age of a class of 24 students is 23 years. The average increased by 1 when the teacher's age also included. What is the age of the teacher?

 Option A: 40

 Option B: 41

 Option C: 48

 Option D: 52

 Option E: 43
[EX A]:
Option C