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: A seller of used cars has 18 cars to sell and each of his clients selected 3 cars that he liked most. If each car was selected exactly thrice, how many clients visited the garage?

 Option A: 8

 Option B: 10

 Option C: 12

 Option D: 18

 Option E: 16
[EX A]: Option D

[EX Q]: 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
[EX A]: Option E

[EX Q]: Question: In a class, the average age of 30 boys is 13 years and the average of 20 girls is 12 years. what is the average age of the whole class?

 Option A: 12.6 Years

 Option B: 12 Years

 Option C: 12.3 Years

 Option D: 13 Years

 Option E: 14 Years
[EX A]:
Option A