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).

[EX Q]: Calculate prob of sequence vgg when three letters picked without replacement from {v: 9, g: 5}.
[EX A]: 15/182

[EX Q]: Suppose -c + 4*v + 2 = -24, -4*c - 3*v + 9 = 0. Solve 2*b - c = -b for b.
[EX A]: 2

[EX Q]: Two letters picked without replacement from {f: 2, z: 5}. What is prob of sequence zf?
[EX A]:
5/21