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: what is the compound interest paid on a sum of rs. 3000 for the period of 2 years at 10 % per annum.
Options: a. 630, b. 620, c. 610, d. 600, e. none of these

A: a
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Q: Problem: students at a school were on average 180 cm tall. the average female height was 170 cm, and the average male height was 182 cms. what was the ratio of men to women ?
Options: a. 5: 2, b. 5: 1, c. 4: 3, d. 4: 1, e. 3: 1

A: b
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Q: Problem: there are 15 balls in a jar. you take out 3 blue balls without putting them back inside, and now the probability of pulling out a blue ball is 1 / 3. how many blue balls were there in the beginning ?
Options: a. 12., b. 9., c. 8., d. 7., e. 6.

A:
d
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