Question

The internal dimensions of a box are 1.2 m,80 cm and 50 cm.How many cubes each of edge 7 cm can be packed in the box with faces parallel to the sides of the box.Also,find the space left empty in the box.

Answer 1

TSA of the box=2(lb+bh+hl)
                       =2(120*80+80*50+120*50)
                       =2(9600+4000+6000)
                       =2*19600
                       =39200 cm^2
TSA of one cube=6a^2
                          =6*49
                          =294 cm^2
No. of cubes that can be packed into the box=39200/294
                                                                    =133
Space left=39200-133*24
               =39200-39102
               =98 cm^2

Hope this helps ;)