The equation for surface area of a box is
[tex]a = 2(wl + hl + hw)[/tex]
So if we substitute the measurements into the equation we get
[tex]a = 2(4 \times 5 + 3 \times 5 + 3 \times 4)[/tex]
and with some calculations, that would equal
[tex]a = 2(20 + 15 + 12)[/tex]
[tex]a = 2(47)[/tex]
[tex]a = 94[/tex]
The total area for the box is 94 inches². Hope this helps!