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: The average runs scored by a batsman in 20 matches is 40. In the next 10 matches the batsman scored an average of 20 runs. Find his average in all the 30 matches?

 Option A: 31

 Option B: 46

 Option C: 88

 Option D: 33.33

 Option E: 12

SOLUTION: Option D

PROBLEM: Question: Sixty percent of the members of a swim club have passed the lifesaving test. Among the members who have not passed the test, 12 have taken the preparatory course and 30 have not taken the course. How many members are there in the swim club?

 Option A:  60

 Option B:  80

 Option C:  100

 Option D:  120

 Option E:  140

SOLUTION: Option E

PROBLEM: Question: A set of numbers has the property that for any number t in the set, t + 2 is in the set. If -1 is in the set, which of the following must also be in the set?
I. 5
II. 1
III. -5

 Option A: I only

 Option B: II only

 Option C: I and II only

 Option D: II and III only

 Option E: I, II, and III

SOLUTION:
Option C