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: walking at 4 / 5 of her normal speed, a worker is 10 minutes later than usual in reaching her office. the usual time ( in minutes ) taken by her to cover the distance between her home and her office is
Options: a. 30, b. 35, c. 40, d. 45, e. 50

A: c
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Q: Problem: an optometrist charges $ 150 per pair for soft contact lenses and $ 85 per pair for hard contact lenses. last week she sold 5 more pairs of soft lenses than hard lenses. if her total sales for pairs of contact lenses last week were $ 1,220, what was the total number of pairs of contact lenses that she sold ?
Options: a. 9, b. 13, c. 15, d. 17, e. 19

A: a
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Q: Problem: a, b and c invests rs. 2000, rs. 3000 and rs. 4000 in a business. after two year a removed his money; b and c continued the business for one more year. if the net profit after 3 years be rs. 4800, then a ' s share in the profit is ?
Options: a. 600, b. 400, c. 678, d. 867, e. 768

A:
e
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