Hello everyone today we are going to start with the session called introduction to profit and loss which comes under profit loss and discount now this session is an application of percentages and hence the base required for the session is one is reciprocals and its percentages and the second is percentage increase and percentage decrease so let’s begin with some basic definitions I can say the price at which we buy the article is the cost price and the price in which we sell the article is the selling price if the selling price is more than the cost price that I can say is a case of profit and if the selling price is less than the cost price then I can say is a case of loss now I am considering an example here there is a Anand sandwich seller he is able to buy the raw material required to make sandwich at rupees 120 now using this raw materials he is able to make 6 sandwiches each one he sells at rupees 25 so can I say the total selling price is a 25×6 that is 150 rupees yes now suppose if he is buying at 120 and he is selling at 150 so can I say its a case of profit that is profit is nothing but selling price minus cost price that is 150 – 120 that is 30 rupees the base for calculating percentage profit is cost price and hence percentage profit is profit upon cost price into 100 in our case the profit is 30 on the base of 120×100 can I say 30/120 is 1 by 4 and 1 by 4 in percentage is 25% now let us consider the second situation the 2nd situation is is buying the raw material at 120 but in this case is able to make only 4 sandwiches so can I say the selling price would be 25×4 that is 100 rupees now he is buying at 120 is selling at 100 rupees so can I say he is making a lost here this loss is hence defined as cost price minus selling price that is in our case 120 minus 100 that is 20 rupees the percentage loss is again on the base of cost price that is loss supon cost price into 100 in our case 20/120 into 100 can I say 20/120 is 1 upon 6 that is 1 upon 6 in percentage is 16.67 percentage the learning from these two examples is first profit is selling price minus cost price and loss is cost price minus selling price and both percentage profit and percentage loss are calculated on the base of cost price so that it shows that the base for calculating profit or loss percentage is always the cost price now let’s begin with one statement that is a shopkeeper sells an article for 20% profit how can we evaluate this statement there are four methods to work with the first method is.