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).

Let u be (285/38)/(1/4). Suppose d = 5*x - 3, 0*d = -4*d - 5*x + 13. Solve 0 = 4*n - 3*f - 13 - 18, -5*n + d*f + u = 0 for n.
4

Four letters picked without replacement from zczcuzuzuzccuzzcc. Give prob of picking 4 c.
3/476

Calculate -162 divided by -1.

162