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: mary works in a restaurant a maximum of 70 hours. for the first 20 hours, she is paid $ 8 per hour. for each overtime hour, she is paid at a rate which is 25 % higher than her regular rate. how much mary can earn in a week ?
Options: a. 600, b. 620, c. 660, d. 320, e. 400

Answer: c

Question: Problem: p has $ 32 more than what q and r together would have had if both b and c had 1 / 6 of what p has. how much does p have ?
Options: a. $ 44, b. $ 48, c. $ 52, d. $ 56, e. $ 60

Answer: b

Question: Problem: two bullet train s 140 m and 210 m long run at the speed of 60 km / hr and 40 km / hr respectively in opposite directions on parallel tracks. the time ( in seconds ) which they take to cross each other, is :
Options: a. 15.8 sec., b. 12.6 sec., c. 11.8 sec., d. 10.8 sec., e. 08.8 sec.

Answer:
b