• # question_answer If the cost price of 20 greeting cards is equal to the selling price of 16 greeting cards. Find the gain or loss percent A)  20%                           B)  30%C)  25%   D)  40%

(c): C.P of 20 greetings = S.P of 16 greeting Let C.P of greeting card be 'x?. Let gain % be r% $\therefore S.P=x\left( 1+\frac{r}{100} \right)\Rightarrow$S.P. of 16 cards $=16x\left( 1+\frac{r}{100} \right)$ $\Rightarrow 20x=16x\left( 1+\frac{r}{100} \right)$ $\Rightarrow \frac{4}{5}=\left( 1+\frac{r}{100} \right)$             $\Rightarrow \frac{1}{4}=\frac{r}{100}\Rightarrow r=25%$