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 age of 31 students in a group is 16 years. when teacher's age is included to it, the average increases by one.What is the teacher's age in years?

 Option A: 31

 Option B: 36

 Option C: 48

 Option D: 45

 Option E: 57

SOLUTION: Option C

PROBLEM: Question: For all integers x>1. <x>=2x+(2x-1)+(2x-2)+......2+1. What is the value of <2>*<4>?

 Option A:  60

 Option B:  116

 Option C:  210

 Option D:  263

 Option E:  360

SOLUTION: Option E

PROBLEM: Question: A die is rolled twice. What is the probability of getting a sum equal to 9?

 Option A: 2/3

 Option B: 2/9

 Option C: 1/3

 Option D: 1/9

 Option E: 1/10

SOLUTION:
Option D