poly
posted by srilee on .
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.