Question

if the cost price of 15 pens is equal to the selling price of 20 pens, find the gain or loss percent.​

Answer 1

Let the cost price of a pen = C

So cost of 15- pens= 15C

If the selling price of a pen= S then the Selling Price of 20- pens = 20S

So 15C= 20S

S= 15/20= 3/4 C

Loss % =( C.P- S.P)/S.P x100

Loss % = (C-3/4C)/C x 100

= Loss % = 25% .

Answer 2

Refer to the above attachment !!