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?

Answer 1

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.