instruction:
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).
question:
What is prob of sequence kcv when three letters picked without replacement from kkkckvknnknvkn?
answer:
1/156


question:
0.3539 - 5
answer:
-4.6461


question:
Solve -31 = -4*d + 7*d - 5*u, -4*u = 5*d - 10 for d.
answer:

-2