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 value of n if the sum of the consecutive odd intergers r from 1 to n equals 169 ?
Options: a. 47, b. 25, c. 37, d. 33, e. 29

A: b
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Q: Problem: a bag has 9 green balls and 23 pink balls. how many green balls should be added to the bag so that the ratio of green balls and pink balls in the bag becomes 1: 1 ?
Options: a. 10, b. 11, c. 12, d. 13, e. 14

A: e
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Q: Problem: xavier, yvonne, and zelda each try independently to solve a problem. if their individual probabilities for success are 1 / 4, 2 / 3 and 5 / 8, respectively, what is the probability that xavier and yvonne, but not zelda, will solve the problem ?
Options: a. 1 / 16, b. 7 / 8, c. 9 / 64, d. 5 / 64, e. 3 / 64

A:
a
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