Answer: 84 ft
Step-by-step explanation:
Remark
The best way would be to make a duplicate of this page and cut out the shapes. Then find out which ones fold into a cube. It would also be the most time consuming.
The second best way is to imagine how each flat surface would fold to make a cube. I think C would and D would. I don't think the other 2 would.
Your friend has 30 you have 15
you are counting by 5 I believe for each box
x-2=7
apply additon property of equality
x-2+2=7+2
x=9
