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: if x + y = 260, x - y = 200, for integers of x and y, y = ?
Options: a. 200, b. 230, c. 50, d. 115, e. 150

A: b
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Q: Problem: a shop owner professes to sell his articles at certain cost price but he uses false weights with which he cheats by 12 % while buying and by 30 % while selling. what is his percentage profit ?
Options: a. 10.22 %, b. 20.22 %, c. 21.22 %, d. 60 %, e. ca n ' t be calculated

A: d
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Q: Problem: an alloy of copper and zinc contains copper and zinc in the ratio 8: 2. another alloy of copper and zinc contains copper and zinc in the ratio 4: 6. in what ratio should the two alloys be mixed so that the resultant alloy contains equal proportions of copper and zinc ?
Options: a. 5: 1, b. 4: 1, c. 3: 1, d. 6: 1, e. 8: 1

A:
c
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