Question

If each edge of a cube is increased by 100% then percentage increase in its surface area =

• A. 400 %
• B. 300 %
• C. 200 %
• D. 100 %

Answer 1

The correct option is B 300 %

Let the edge $=acm$
New measure of edge after increase $=2a$ as it increased by $100\%$.
Total surface area of original cube $=6a^2$
TSA of new cube = $6\times (2a{)}^2=6\times 4a^2$
= $24a^2$
= 4 $\times$ Total surface area of original cube
Increase in area = TSA of new cube - TSA of original cube
=4 $\times$ Total surface area of original cube$-$TSA of original cube
= 3 $\times$ Total surface area of original cube
$\therefore$ percentage increase in surface area =300 $\%$