Question

if the length and breadth of a rectangle of are doubled how many times the perimeter of the old rectangle will that of the new rectangle be?

Answer 1

perimeter of old rectangle=
$= 2(l + b)$
new rectangle-->length=2l
breadth=2b
perimeter of new rectangle=>
$= 2(2l + 2b)$
$= 2 \times 2(l + b)$
$= 4(l + b)$
=>perimeter of new rectangle-perimeter of old rectangle
$= 4(l + b) - 2(l + b)$
$= 2(l + b)$
therefore, the new rectangle has perimeter 2(l+b) units more than the old one.