Answer:
No. The actual total surface area is double that: 108 in².
Explanation:
The area Charlotte has computed is the area of the faces you can see. There are three other faces you cannot see that are the same size. So, the total area is double the amount Charlotte has computed.
A = 2(LW +H(L+W)) = 2(6·4+3(6+4)) = 2(24+30) = 2(54) = 108 . . . . sq in