A man spent exactly $2.50 on 3¢, 6¢, and 10¢ stamps. If he bought ten 3¢ stamps and
twice as many 6¢ stamps as 10¢ stamps, how many 10¢ stamps did he buy?
twice as many 6¢ stamps as 10¢ stamps, how many 10¢ stamps did he buy?