Rahul purchases some no. of oranges at the rate of 12 oranges for Rs.1. How many should he sell in rupees one to gain 20%?

7 10 12 8

10

CP of one orange = \(\frac{1}{12}\) SP of one orange = \(\frac{1}{12}\) × \(\frac{6}{5}\) = \(\frac{1}{10}\) Therefore, he should sell 10 oranges for Rs. 1.