Cereal is packaged in a box shaped like a rectangular prism with a base 7.5 inches by 2 inches and a height of 10 inches. manufacturing each box requires 10% more cardboard than the box's surface area. how much cardboard is needed to make each box?

The first thing we must do in this case is to calculate the surface area of the rectangular prism.
 We have then:
 A = 2 * ((L * h) + (L * w) + (h * w))
 Where,
 L: long
 w: width
 h: height
 Substituting the values:
 A = 2 * ((7.5 * 10) + (7.5 * 2) + (10 * 2))
 A = 220
 Then, "Manufacturing each box requires 10% more cardboard than the box's surface area"
 Ar = 220 * 1.10
 Ar = 242
 242-220 = 22
 
 is needed 22 in ^ 2 cardboard to make each box

Iam pretty sure its a sorry if im wrong