23
Those are not the answer:
1) 20 - can be divided by 2
2) 21 - can be divided by 3
3) 22 - can be divided by 2
4) 24 - can be divided by 2 and 4.
5) 25 - can be divided by 5
6) 26 - can be divided by 2
7) 27 - can be divided by 3
8) 28 - can be divided by 2 and 4
A rectangle, presumably, as the cross section is going to be whatever shape the outward faces are (in the case of a vertical cross section like this one)
Answer:
Step-by-step explanation:
2(5*4)+2(4*3)+2(3*5)=94 sq.m (Orginial SA)
2(4*5)+2(5*6)+2(6*4)=148 sq.m (Total SA)
148-94=54 (New SA)
