Question

if each side of a square be increased by 10% the percentage increase in area is a) 10%, b) 100%, c) 25% , d) 21%

Answer 1

+10+10+(10×10/100)% = 21%

Answer 2

$\pink { If \:side \:of \: square \:is \: increased }\\\pink {by\:x\% , then \:the \:area \:will }\\\pink{ increase \:by }\\\orange { \Big(2x + \big(\frac{x}{10}\big)^{2}\Big) \% }$

$Here , Side \:of \:a \: square \:be \:increased \\by \: x = 10\%$

$Percentage \: increase \:in \:area \\= 2\times 10 +\big( \frac{10}{10}\big)^{2} \\= 20 + 1^{2}\\= 20 + 1\\= 21\%$

Therefore.,

$Option \: \pink { (d) } \: is \: correct.$

•••♪