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: There are some pigeons and hares in a zoo. If heads are counted, there are 120. If legs are counted, there are 580. The number of hares in the zoo is?

Option A: 20

Option B: 82

Option C: 190

Option D: 137

Option E: 170

SOLUTION: Option E

PROBLEM: Question: On a trip covering 350 km, a bicyclist travels the first 200 km at 20 km per hour and the remainder of the distance at 15 km per hour. What is the average speed, in km per hour, for the entire trip?

Option A: 15.5

Option B: 16.0

Option C: 17.5

Option D: 19.0

Option E: 18.5

SOLUTION:
Option C