justin had nickels and dimes in his pocket. When he counted out his change, he had 80 cent. if there are 12 coins altogether, how many dimes did he have?
n+d = 12
5n+10d = 80 or n + 2d = 16
subtract them ---> d = 4
sub into first --- n+4=12
n = 8
he has 8 nickels and 4 dimes.