Given a math problem with context and a question and 5 answer choices, the task is to provide the correct answer choice based on the problem. You must choose one of the given answer choices by letter: a, b, c, d, or e; anything else is invalid.

[EX Q]: Problem: when x is multiplied by 3, the result is 10 more than the result of subtracting x from 26. what is the value of x ?
Options: a. - 4, b. 9, c. 11, d. 13, e. 22
[EX A]: b

[EX Q]: Problem: what number must be added to 6, 16 and 8 to get an average of 13 ?
Options: a. 23, b. 22, c. 44, d. 33, e. 55
[EX A]: b

[EX Q]: Problem: george does 3 / 5 th of a piece of work in 9 days. he then calls in paul and they finish the work in 4 days. how long would paul take to do the work by himself ?
Options: a. 10, b. 20, c. 30, d. 40, e. 50
[EX A]:
c