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).

Input: Consider Input: Three letters picked without replacement from {e: 4, z: 1, r: 9}. What is prob of picking 3 r?

Output: 3/13


Input: Consider Input: Solve -182 = -4*z - 194, -2*a + 2*z + 4 = 0 for a.

Output: -1


Input: Consider Input: Two letters picked without replacement from emltz. What is prob of sequence el?


Output: 1/20