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 w = -31583/220 - -1550/11. What is the common denominator of -97/10 and w?
[A]: 20


[Q]: What is prob of picking 4 y when four letters picked without replacement from yyyyyyyymmmymm?
[A]: 18/143


[Q]: Two letters picked without replacement from {r: 3, l: 6, j: 6, u: 3}. What is prob of picking 1 u and 1 r?
[A]:
1/17