Answer:
She used 600 square inches of paper.
Explanation:
Since the box are 15 in x 10 in x 2 in and are stacked on top of each other, they form a bigger rectangular prism with 15 in x 10 in x 6 in. In order to calculate how much paper she used, we need to calculate the surface area of this prism, this is done by using the following formulla:
surface area = 2*width*length + 2*width*height + 2*length*height
surface area = 2*15*10 + 2*15*6 + 2*10*6 = 300 + 180 + 120
surface area = 600 in².
She used 600 square inches of paper.