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]: Three letters picked without replacement from {q: 5, b: 3, o: 1}. What is prob of picking 1 o and 2 b?
[A]: 1/28


[Q]: What is 0.7 take away 271816?
[A]: -271815.3


[Q]: Let b(l) = l**3 - 2*l**2 - 3*l. Let g be b(3). Solve g*f + 15 = -3*f for f.
[A]:
-5