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: a bag of potatoes weighs 60 lbs divided by half of its weight. how much does the bag of potatoes weight ?
Options: a. 20 lb, b. 11 lb, c. 10 lb, d. 15 lb, e. 5 lb

A: b
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Q: Problem: the price of a book is increased from $ 300 to $ 390. what is the % of increase in its price ?
Options: a. 10 %, b. 20 %, c. 30 %, d. 35 %, e. 45 %

A: c
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Q: Problem: sandy is younger than molly by 6 years. if their ages are in the respective ratio of 7: 9, how old is molly ?
Options: a. 21, b. 24, c. 27, d. 36, e. 45

A:
c
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