Profit and loss are determined by the value of cost price and selling price. Cost price is the price at which an article is purchased and selling price is the price at which article is sold 

Profit = selling price – cost price

Loss = cost price – selling price

\[\% \;{\rm{Profit}} = \left( {\frac{{{\rm{selling}}\,\,\,{\rm{price}}\,\, - \,\,{\rm{cost}}\,\,{\rm{price}}}}{{{\rm{cost}}\,\,{\rm{price}}}}} \right) \times 100\]

\[\% {\rm{Loss}} = \left( {\frac{{{\rm{cost}}\,\,{\rm{price}}\,\, - \,\,{\rm{selling}}\,\,\,{\rm{price}}}}{{{\rm{cost}}\,\,{\rm{price}}}}} \right) \times 100\]Percentage profit and loss are always calculated on cost price only. If it is specifically mentioned that percentage profit or loss are to be calculated on selling price, then 

\[\% \;{\rm{Profit}} = \left( {\frac{{{\rm{selling}}\,\,\,{\rm{price}}\,\, - \,\,{\rm{cost}}\,\,{\rm{price}}}}{{{\rm{selling}}\,\,{\rm{price}}}}} \right) \times 100\]

\[\% {\rm{Loss}} = \left( {\frac{{{\rm{cost}}\,\,{\rm{price}}\,\, - \,\,{\rm{selling}}\,\,\,{\rm{price}}}}{{{\rm{selling}}\,\,{\rm{price}}}}} \right) \times 100\]

Questions 01: A dry  fruit seller purchased 3 kinds of nuts at the rate of Rs. 100/kg, Rs. 80/kg and Rs. 60/kg. He then mixed them, respectively, in the ratio 3 : 4 : 5 by weight and sold the same to a customer at 50% profit. The price at which he sold to the customer is:

(1) Rs 115
(2) Rs 90
(3) Rs 70
4) Rs 120

MARKED PRICE:

Marked price is also known as the list price. It is the price which is marked on the article.

Mark up percentage =\(\frac{{{\rm{MP}}\; - \;{\rm{CP}}}}{{{\rm{CP}}}} \times 100\), where CP = cost price and MP = marked price