Question

how to solve it? ...

Answer 1

Let the side of cube be x then total surface area will be
${6}^{2}$
so 6
$6{x}^{2}$
when side is doubled then side will be 2x Now total surface area will be
${24x}^{2}$
Now the increse in Surface area is
${18x}^{2}$
So percentage increase in area is
${18x}^{2} \div {6x}^{2} \times 100$
That is 300 %

Answer 2

Let the side=x
then the TSA=6x²
Also,
New side=2x
then the new TSA=6(2x)²
                              =6*4x²
                              =24x²
Hence,
Old TSA/New TSA *100
=24x²/6x²*100
=4*100
=400 percent
Hence its TSA will increase by 400 percent