Question

Total surface area of a box of cuboid shape is 500 sq. unit. Its breadth and height is 6 unit and 5 unit respectively. What is the length of that box ?

Answer 1

Let the length of the box be l units.

Breadth of the box, b = 6 units

Height of the box, h = 5 units

Total surface area of the box = 500 square units

∴ 2(lb+ bh + hl) = 500 square units

$$\begin{gathered} \Rightarrow l\times 6+6\times 5+5\times l=\frac{500}{2}=250 \\ \Rightarrow 6l+30+5l=250 \\ \Rightarrow 11l=250-30=220 \\ \Rightarrow l=\frac{220}{11}=20\mathrm{units} \end{gathered}$$
Thus, the length of the box is 20 units.