Question

If a cuboid having sides 30×50×40 is divided into 8 equal parts by cutting 3 times.. then find out the total surface area of all the parts

Answer 1

The formula for total surface area of cuboid is 2lw+2lh+2hw; where length (l), width (w), and height (h).

l=30, w=40, w=50

So, total surface area = 2(30x40x50) = 2(60000) = 120000.

Now, it is divided into 8 equal parts : so, total surface area of each part is 120000/8 = 15000. (Ans)

Answer 2

A Cuboid of dimensions 30 × 50 × 40 is divided into 8 part by cutting 3 times .
It means each dimension { e.g., Length Breadth and height} cut in two equal parts as shown in figure . 

I mean after cutting each new Cuboid will be 15 × 25 × 20 
Let Length = 25 , Breadth = 20 and height = 15 of each Cuboid .

We know, the formula, 
total surface of Cuboid = 2[ L × B + B × H + H × L ] 

so, total surface area of each Cuboid = 2[ 25 × 20 + 20 × 15 + 15 × 25 ]
= 2 [ 500 + 300 + 375 ]
= 2 [ 1175 ] = 2350 square unit 

hence, Total surface area of each part = 2350 square unit 

Total surface area of all the eight parts = 2350 × 8 = 18800 square unit