Final answer:
To find the number of hazardous waste sites in state Y, we use the equation 57 = 3n - 12 and solve for n to determine that there were 23 federal hazardous waste sites in state Y.
Step-by-step explanation:
To solve for the number of hazardous waste sites in state Y, given the number of sites in state X, we can set up an equation based on the information provided. We know that the number of sites in state X is 12 less than three times the number of sites in state Y. Let's denote the number of hazardous waste sites in state Y as n.
The equation based on the given information is:
57 = 3n - 12
To find n, we must isolate the variable on one side of the equation. We begin by adding 12 to both sides of the equation:
57 + 12 = 3n - 12 + 12
69 = 3n
Next, we divide both sides by 3 to get n:
n = 69 / 3
n = 23
Therefore, there were 23 federal hazardous waste sites in State Y.