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: x does a work in 20 days. y does the same work in 40 days. in how many days they together will do the same work ?
Options: a. 10, b. 12, c. 20, d. 30, e. 13.33

A: e
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Q: Problem: 2.205 divided by 0.3 gives
Options: a. 7.35, b. 6.25, c. 8.15, d. 6.95, e. none of these

A: a
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Q: Problem: from a pack of cards, two cards are drawn one after the other, with replacement. what is the probability that the first card is a black card and the second card is a king ?
Options: a. 1 / 26, b. 1 / 13, c. 3 / 52, d. 3 / 26, e. 15 / 26

A:
a
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