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]: Two letters picked without replacement from {t: 1, z: 1, v: 1, b: 1, s: 1, p: 2}. What is prob of picking 1 t and 1 p?
[EX A]: 2/21

[EX Q]: ((-57)/(-456))/((-3)/(-8))
[EX A]: 1/3

[EX Q]: Solve 4*i - 28 = 18*i for i.
[EX A]:
-2