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.
--------
Question: Problem: the average of 11 10 prime numbers which are odd is ?
Options: a. 17.72, b. 18.52, c. 19.63, d. 16.53, e. 15.63

Answer: a


Question: Problem: john and david can finish a job together in 2 hours. if john can do the job by himself in 3 hours, what percent of the job does david do ?
Options: a. 36.33 %, b. 33.33 %, c. 39.33 %, d. 40.33 %, e. 33 %

Answer: b


Question: Problem: i bought two books; for rs. 470. i sold one at a loss of 15 % and other at a gain of 19 % and then i found each book was sold at the same price. find the cost of the book sold at a loss ?
Options: a. 274.17, b. 280.17, c. 299.17, d. 266.17, e. 279.17

Answer:
a