Let x represent the number of t-shirts sold, and y represent the number of baseball hats sold. We can create the following system of linear equations to represent this problem:
15x + 12y = 1146
x + y = 84
To solve this system of equations, we can first solve for x in the second equation by subtracting y from both sides:
x = 84 - y
Substituting this expression for x in the first equation, we get:
15(84 - y) + 12y = 1146
Expanding the left side of the equation gives us:
1260 - 15y + 12y = 1146
Combining like terms on the left side gives us:
1260 - 3y = 1146
Adding 3y to both sides gives us:
1260 = 1146 + 3y
Subtracting 1146 from both sides gives us:
114 = 3y
Dividing both sides by 3 gives us:
38 = y
Substituting this value for y in the equation x = 84 - y, we get:
x = 84 - 38
Simplifying this equation gives us:
x = 46
Therefore, the school volleyball team sold 46 t-shirts and 38 baseball hats.