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]: Four letters picked without replacement from {e: 3, q: 9, r: 1, o: 2, c: 3}. Give prob of sequence ccoq.
[A]: 1/680


[Q]: What is prob of sequence ggg when three letters picked without replacement from ccccggcgcgccccgcgcc?
[A]: 20/969


[Q]: What is the next term in 393, 392, 391, 390, 389, 388?
[A]:
387