TASK DEFINITION: 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.
PROBLEM: Question: If x is an integer such that 5 < x < 21, 7 < x < 18, 13 > x > 2, 12 > x > 9, and x + 1 < 13, then x is

 Option A: 3

 Option B: 5

 Option C: 7

 Option D: 9

 Option E: 11

SOLUTION: Option E

PROBLEM: Question: Look at this series: 15, 15, 27, 27, 39, 39, 51, 51, 63, 63, ? ... What number should fill the blank?

 Option A: 51

 Option B: 39

 Option C: 75

 Option D: 15

 Option E: None

SOLUTION: Option C

PROBLEM: Question: In a shop, the profit is 320% of the cost. If the cost increases by 25% but the selling price remains constant, find out approximately what percentage of the selling price is the profit?

 Option A: 20%

 Option B: 30%

 Option C: 40%

 Option D: 50%

 Option E: 70%

SOLUTION:
Option E