Given a simple high-school level math question, you are required to solve it and provide the final answer. The final answer is always a single number. These questions can range from a variety of topics like simple arithmetic, solving equations, converting a quantity from one unit to another, finding remainders/GCD/LCM, finding probabilities etc. Each question has only one correct answer. This answer can be a positive or negative integer, a fraction or a decimal number. If the answer is a negative number use the hyphen (e.g. -42) symbol for the minus sign. For decimal numbers, do not add extra zeros after the decimal point. For fractional numbers, separate the numerator and denominator using a forward slash (e.g. 3/25).
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Question: Four letters picked without replacement from {w: 2, k: 1, o: 1, a: 2, b: 2}. What is prob of picking 1 k, 2 a, and 1 b?

Answer: 1/35


Question: Suppose 5 = -3*r - 4. Let b(f) = 3*f**2 + 2*f - 3. Let c be b(r). Calculate the highest common divisor of c and 6.

Answer: 6


Question: Suppose 3*b + 0 = -2*p + 17, -4*b - 3*p + 22 = 0. What is the highest common factor of 56 and b?

Answer:
7