Profit and Loss

For the purpose of comparison, we usually express the actual profits or loss as a percentage of cost price.
For example, a shopkeeper sold an article for Rs.60 which costs Rs.50 and another article sold for Rs.110 which cost Rs.100. In each case, shopkeeper makes a profit of Rs.10. It seems that in both cases profit is equally gained.
But in percentage profit, we have
Percentage Profit = \frac{{10}}{{50}}x 100% = 20%
Percentage Profit = \frac{{10}}{{100}}x 100% = 10%
Hence, in first case he made a more profit than in 2nd case, this is better and accurate method for comparison.

A bag costing Rs.28 sold for Rs.35. Find percentage profit.
Let       Cost Price = Rs.28
            Selling Price = Rs.35
            Profit = Selling Price – Cost Price = 35 – 28 = Rs.7
            Percentage Profit = \frac{7}{{28}} x 100% = 25%

A machine costing Rs.60 and sold for Rs.50. Find percentage loss.
Let       Cost Price = Rs.60
            Sold Price = Rs.50
            Loss = Cost Price – Sold Price = 60 – 50 = Rs.10
            Percentage Loss = \frac{{10}}{{60}} x 100% = 16\frac{2}{3}%