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]: What is prob of picking 2 v and 1 x when three letters picked without replacement from xmxvxmvvmmxmvx?
[EX A]: 15/182

[EX Q]: Solve 96*r - 13 = 91*r + 2*u, 3*u - 12 = -3*r for r.
[EX A]: 3

[EX Q]: What is prob of sequence xxs when three letters picked without replacement from xsxssxxsxxxxs?
[EX A]:
70/429