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).

[Q]: Suppose 2*y + 12 = 6*y. Suppose y = f - 15. Solve -8 = -4*w, -3*d - 4*w + f = -8*d for d.
[A]: -2


[Q]: Let i = -28 - -30. Suppose 4*z + 5*k = 200, -i*z + 81 = -k - 33. What is the tens digit of z?
[A]: 5


[Q]: How many seconds are there in 7.470708 microseconds?
[A]:
0.000007470708