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: Two letters picked without replacement from xhtxihxghxhthxx. What is prob of sequence hi?

Answer: 1/42


Question: Evaluate (-7)/6 + 2 + 9/(-27).

Answer: 1/2


Question: Two letters picked without replacement from {o: 2, y: 4, u: 8, d: 1, k: 1}. Give prob of picking 1 d and 1 u.

Answer:
1/15