What is the gain or loss percent if oranges are bought at Rs 9 per dozen and sold at Rs 18 per 20 oranges?

Solution:
Here the cost price of 1 orange =Rs9/12
=Rs 0.75
Selling price of 1 orange=Rs 18/20
=Rs 0.90
There is profit , because selling price is higher than cost price in the above answers.
Now,
Profit percent=(profit/cost price)X100
=(0.9-0.75)X100
=15%