Question

If the cost price of $9$ pens is Rs. $11$ and the selling price of $11$ pens is Rs. $9$, find the profit or loss in percent.

Answer 1

C.P. : 9 pens Rs. 11

S.P. : 11 pens Rs. 9

Remark: Make the C.P. and S.P. equal and hence multiplying them by 9 and 11 respectively.

C.P. : 9 $\times$ 9 pens (articles 9 $\times$ 9)

S.P. : 11 $\times$ 11 pens (articles 11 $\times$ 11)

Since, cost price of 81 pens is equal to selling price of 121 pens, hence there its loss.

Loss (%) $=\frac{121-81}{121}\times 100$

$=\frac{40}{121}\times 100$

$=33.06$%