Question

The cost price of 21 articles is equl to selling price
of 18 articles. Find the gain or loss percent ?​

Answer 1

$\huge{\boxed{\mathfrak{\underline{Answer}}}}$

$\large{\sf{Assume \: that \: the \: SP \: of \: one \: article \: be \: Rs1.}}$

$\large{\sf{So\: the \: SP \: of \: 18 \: articles \: = \: Rs 18}}$

$\large{\sf{Assume \: that \: SP \: be \: x}}$

$\large\sf{So,}$

$\large{\sf{21x \: = \: 18}}$

$\large{\rightarrow{\sf{x \: = \: {\frac{18}{21}}}}}$

$\sf\large{Therefore,}$

$\large\sf{Profit \: = \: SP \: - \: CP}$

$\large\sf{Profit \: = \: {1- {\frac{ 18}{21}}}}$

$\large{\sf{Profit \: = {\frac{3}{21}}}}$

$\large{\sf{Profit \: Percent \: = \: {frac{Profit}{CP*}}100}}}$

$\large\sf{Profit Percent \: = \: Profit/18/21 * 100}$

Profit % = 3/21/18/21 * 100

Profit % = 16.66 %

Answer 2

$\textbf{\underline{\underline{According\:to\:the\:Question}}}$

★Assume the SP of 1 article

= Rs. 1

★Hence SP of 18 articles :-

= Rs. 18

${\boxed{\sf\:{Assume\;CP\;be\;p}}}$

★Therefore :-

21p = 18

$\tt{\rightarrow p=\dfrac{18}{21}}$

★Here we get :-

${\boxed{\sf\:{SP\;is\;greater\;than\;CP}}}$

Gain = SP - CP

$\tt{\rightarrow 1-\dfrac{18}{21}}$

$\tt{\rightarrow\dfrac{3}{21}}$

$\tt{\rightarrow Gain=\dfrac{Gain}{CP}\times 100}$

$\tt{\rightarrow Gain=\dfrac{3/21}{18/21}\times 100}$

= 16.66%