A fruitseller by means of a false balance cheats $20$% in buying and also cheats the buyer to the same extent in selling. Find the gain percent on his outlay.
My Approach:
He cheats $20$% on purchasing means; He pays only Rs. $100$ which worth Rs. $120$.
Again, he cheats $20$% on selling means; He sells the fruits worthing Rs. $100$ for Rs. $120$.
Now, what should I do? Please help me to continue.