Question

From a sheet of 20 m$\times$10 m, 4 squares of side 2.5 m are cut out from the corners and made into a box.$\text{TSA}\mathrm{of}\mathrm{the}\mathrm{box}$ =

• A. 150 m${}^2$
• B. 100 m${}^2$
• C. 175 m${}^2$

Answer 1

The correct option is C 175 m${}^2$

A square of side 2.5 m is cut off from all the corners. Therefore the length of a rectangular sheet changes to 15 m (20 - 2 $\times$ 2.5) and breadth to 5 m (10 - 2 $\times$ 2.5).

Therefore,
surface area of the resulting figure
= sum of areas of I, II, III, IV, V

= (15 $\times$ 2.5) + (5 $\times$ 2.5) + (15 $\times$ 2.5) + (5 $\times$ 2.5) + (15 $\times$ 5)
= 175 $m^2$