Answer:
158 inch^2
Explanation:
To know how much paper he needs, we need to find the surface area of the box he wants to mail and thats the amount of paper.
Surface area of cuboidal box:
= 2( lh+bh+lb)
where l is length
b is breadth
h is height
= 2( 5*3+8*3+5*8)
= 2 ( 15+24+40)
= 2*79
= 158 inch^2 of paper