Question

the percentage increase in the area of rectangle of each sides is increased by 20% is

Answer 1

$let \: length \: \: be \: \: l \: \: and \: breadth \: \: be \: \: b \\ then \: \: area = lb \\ after \: \: increase \: \: by \: \: 20\% \\ length \: \: becomes \: \: 1.2l \\ breadth \: \: becomes \: \: 1.2b \\ then \: \: new \: \: area = 1.2l \times 1.2b = 1.44lb \\ \%increase \: \: in \: \: area \\ = \frac{1.44lb - lb}{lb} \times 100 = 44\%$