Question: A trader fixed the price of cosmetic items 30% above the cost price. When he/she sold an item at 25% discount, there was a loss of Rs 15. Find the cost price and marked price of the item.

Solution:

Let MP be the marked price, CP be the cost price, SP be the selling price and d be the discount.

According to the question,
discount percentage (d%) = 25%
loss amount (L) = Rs 15

Here,
MP = CP + 30% of CP

= CP ( 1 + \frac{30}{100})

= CP × \frac{130}{100}

or, MP = \frac{13CP}{10} - (i)


And,
SP = MP ( 1 - \frac{d%}{100})$

= MP ( 1 - \frac{25}{100})

= MP × \frac{75}{100}

= \frac{13 CP}{10} × \frac{3}{4}

= \frac{39 CP}{40}


Given,
Loss = Rs 15

or, CP - SP = 15

or, CP - \frac{39CP}{40} = 15

or, \frac{40CP - 39CP}{40} = 15

or, CP = 15 × 40

\therefore CP = Rs 600


Put value of CP in equation (i), we get,
or, MP = \frac{13 × 600}{10}

\therefore MP = Rs 780

Hence, the required cost price and marked price of the article are Rs 600 and Rs 780, respectively.