7. If U = {1, 2, 3, ..., 9}, A = {2, 3, 4, 5, 6} and B = {3, 6, 9} then find $A \cap B$ and $A \cup B$ and show in Venn-diagram.
8. Convert 10101$_2$ into quinary number system
9. The marked price of an electric fan is Rs. 1600 and shopkeeper allows 5% discount