The width is 3.
A rectangular prism is 3d. This means that there are three dimensions being multiplied by each other to obtain the overall volume. We can use the equation V = lwh to solve this equation, with V being volume, and the following, length, width, height. Substituting in the values (and changing the mixed numbers to improper fractions for simplicity):
1035/4 = (15/2)(23/2)(w)
w = (1035/4)(2/15)(2/23)
w = 3