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.

Q: 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

A: c
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Q: Problem: two guys a and b leave point a and point b simultaneously and travel towards point b and point a on the same route at their respective constant speeds. they meet along the route and immediately proceed to their respective destinations in 32 minutes and 50 minutes respectively. how long will b take to cover the entire journey between point b and point a ?
Options: a. 65, b. 90, c. 70, d. 75, e. 80

A: b
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Q: Problem: kim finds a 2 - meter tree branch and marks it off in thirds and fifths. she then breaks the branch along all the markings and removes one piece of every distinct length. what fraction of the original branch remains ?
Options: a. 3 / 5, b. 2 / 5, c. 7 / 5, d. 1 / 2, e. 8 / 15

A:
a
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