My brother owes me $10. i already have $10. my dads friend gave me and him $20 to split in half. he gave me the $20 and took my $10. does he still owe me. explain plz

Yes...     You have $10
               your brother is supposed to give you $10
               he gives you the money the friend told him to and you would have $20 PLUS the ten that he owes you. That would make you have $30. He took youre ten and gave you 20 but you were supposed to have 20 in the first place. He needs to give you the ten back he owes you. 

The percent discount was 120