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: Suppose -16 = 4*q - 0*q. Let z be (-50)/q + (-1)/(-2). Suppose -2*a + 37 = -67. Calculate the greatest common factor of z and a.

Answer: 13


Question: How many seconds are there in fifteen quarters of a minute?

Answer: 225


Question: Let f(j) = -j**2 - 5*j. Let o be f(-3). Suppose -b = -o*b, 4*x = b + 12. Suppose v = 4*v - x, v = y - 9. What is the tens digit of y?

Answer:
1