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: last year elaine spent 20 % of her annual earnings on rent. this year she earned 35 % more than last year and she spent 30 % of her annual earnings on rent. the amount she spent on rent this year is what percent of the amount spent on rent last year ?
Options: a. 202.5, b. 194.5, c. 197.5, d. 182.5, e. 177.5

A: a
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Q: Problem: a sum of money at simple interest amounts to rs. 720 after 2 years and to rs. 1020 after a further period of 5 years. the sum is :
Options: a. 400, b. 500, c. 600, d. 700, e. 800

A: c
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Q: Problem: how many unique positive odd integers less than 100 are equal to the product of a positive multiple of 5 and an odd number ?
Options: a. 4, b. 10, c. 11, d. 12, e. 15

A:
b
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