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 a lends rs. 3150 to b at 8 % per annum and b lends the same sum to c at 12.5 % per annum then the gain of b in a period of 2 years is ?
Options: a. 280, b. 295, c. 283.5, d. 245, e. 200

A: c
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Q: Problem: the dimensions of a room are 10 m x 7 m x 5 m. there are 2 doors and 3 windows in the room. the dimensions of the doors are 1 m x 3 m. one window is of size 2 m x 1.5 m and the other 2 windows are of size 1 m x 1.5 m. the cost of painting the walls at rs. 3 per sq m is
Options: a. 2488, b. 378, c. 739, d. 474, e. 291

A: d
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Q: Problem: ravi purchased a refrigerator and a mobile phone for rs. 15000 and rs. 8000 respectively. he sold the refrigerator at a loss of 5 percent and the mobile phone at a profit of 10 percent. overall he make a.
Options: a. 50, b. 288, c. 27, d. 200, e. 881

A:
a
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