If each linear dimension is scaled by a factor of 10, then the area is scaled by a factor of 100. This is because 10^2 = 10*10 = 100. Consider a 3x3 square with area of 9. If we scaled the square by a linear factor of 10 then it's now a 30x30 square with area 900. The ratio of those two areas is 900/9 = 100. This example shows how the area is 100 times larger.
Going back to the problem at hand, we have the initial surface area of 16 square inches. The box is scaled up so that each dimension is 10 times larger, so the new surface area is 100 times what it used to be
New surface area = 100*(old surface area) new surface area = 100*16 new surface area = 1600
