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: jack has two dice, one has 6 equally probable sides, labeled 1, 2, 3, 4, 5, 6, and the other has 7 equally probable sides, labeled 1, 2, 3, 4, 5, 6, 7. if jack rolls both dice what is the probability that both of the number ' s sum will be 13 ?
Options: a. 3 / 14, b. 2 / 7, c. 1 / 3, d. 1 / 42, e. 12 / 21

A: d
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Q: Problem: if a person walks at 25 km / hr instead of 10 km / hr, he would have walked 20 km more. the actual distance traveled by him is :
Options: a. 50 km, b. 56 km, c. 13.3 km, d. 70 km, e. 80 km

A: c
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Q: Problem: a sum of money is to be distributed among a, b, c, d in the proportion of 5: 2: 4: 3. if c gets $ 500 more than d, what is c ' s share ?
Options: a. $ 1200, b. $ 1600, c. $ 1800, d. $ 2000, e. $ 2400

A:
d
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