Let's begin by identifying key information given to us:
Length (l) = 5 cm,
Width (w) = 3 cm,
Height (h) = 4 cm
The surface area of a rectangular prism is given by the formula:
[tex]\begin{gathered} s=2\mleft(wl+hl+hw\mright) \\ s=2(3\cdot5+4\cdot5+4\cdot3) \\ s=2(15+20+12)=2(47) \\ s=94cm^2 \end{gathered}[/tex]
Your friend is wrong. He/She made a mistake on line 1 of the solution (the area of one of the sides was repeated twice instead of once)
