Given : 83.33% of 36 coins are 20 paisa coins
83.33% of 36=(83.33100)×36=30
So, 30 coins are 20 paise coins and remaining (36−30)=6 coins are 10 paise coins.
Value =30×20+6×10=660 Paise =Rs.6.60, which is the given amount.
∴ Number of 10 paise coins are 6.