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 van takes 5 hours to cover a distance of 495 km. what speed in kph should the van maintain to cover the same distance in 3 / 2 of the previous time ?
Options: a. 60, b. 63, c. 66, d. 69, e. 72

A: c
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Q: Problem: if the range q of the 6 numbers 4, 314, 710 and x is 12, what is the difference between the greatest possible value of x and least possible value of x ?
Options: a. 0, b. 2, c. 12, d. 13, e. 15

A: d
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Q: Problem: a ladder 30 feet long is leaning against a wall that is perpendicular to level ground. the bottom of the ladder is 10 feet from the base of the wall. if the top of the ladder slips down 5 feet, how many feet will the bottom of the ladder slip ?
Options: a. 14, b. 15, c. 18.92, d. 19, e. 25

A:
c
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