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).

[Q]: Let z = 27 - 9. Suppose 2*t = -3*t - 4*l + 38, 4*l = 5*t - 22. What is the highest common divisor of z and t?
[A]: 6


[Q]: Suppose -4*s - 3 = -47. What is the least common multiple of 21 and s?
[A]: 231


[Q]: Calculate prob of picking 2 x and 1 f when three letters picked without replacement from {f: 11, h: 2, x: 6}.
[A]:
55/323