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 and b started a business investing rs. 80,000 and rs 20,000 respectively. in what ratio the profit earned after 2 years be divided between a and b respectively ?
Options: a. 4: 1, b. 3: 2, c. 18: 20, d. 18: 4, e. 17: 4

A: a
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Q: Problem: if p ( a. = 5 / 7 and p ( b. = 2 / 5, find p ( a n b. if a and b are independent events.
Options: a. 7 / 25, b. 3 / 25, c. 8 / 25, d. 2 / 7, e. 3 / 17

A: d
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Q: Problem: 30 liters of a mixture contains milk and water in the ratio 2: 1. if 5 liters of this mixture be replaced by 5 liters of milk, the ratio of milk to water in the new mixture would be ?
Options: a. 3: 2, b. 3: 1, c. 4: 1, d. 5: 2, e. 2: 1

A:
d
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