Question

Mary wants to decorate her Christmas tree. She wants to place the tree on a wooden block covered with coloured paper with picture of Santa Claus on it. She must know the exact quantity of paper to buy for this purpose. If the box has length, breadth and height as 80 cm, 40 cm and 20 cm respectively. How many square sheets of paper of side 40 cm would she require?

Answer 1

Length of box (l) = 80 cm

Breadth (b) 40 cm

and height (h) = 20 cm

$\therefore \text{Total surface area}=2(lb+bh+hl)$

$=2[80\times 40+40\times 20+20\times 80]c{m}^2$

$=2[3200+800+1600c{m}^2]$

$=2\times 5600=11200c{m}^2$

$\text{Size of paper sheet}=40cm$

$\therefore \text{Area of one sheet}=(40cm{)}^2$

$=1600c{m}^2$

$\therefore \text{No. of sheets required for the box}$$=\frac{11200}{1600}=7sheets$