William bought some tickets to see his favorite singer. He bought some adult tickets and some children tickets, for a total of 15 tickets. The adult's tickets cost $30 per ticket and the children's ti

William bought some tickets to see his favorite singer. He bought some adult tickets and some children tickets, for a total of 15 tickets. The adult's tickets cost $30 per ticket and the children's tickets cost $20 per ticket. if he spent $330 then how many adults and children's tickets did he buy? Do it step by step