TASK DEFINITION: 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).
PROBLEM: Calculate prob of sequence rkk when three letters picked without replacement from {r: 12, k: 3}.

SOLUTION: 12/455

PROBLEM: Divide -651 by 3.

SOLUTION: -217

PROBLEM: Suppose 20 = 5*f - 10. Let g = f - 15. Let y = 15 + g. Solve -4*i - y = -7*i for i.

SOLUTION:
2