Question 1022677
n = number of nickels
d = number of dimes


n + d = 60
5n + 10d = 500


Multiply the first equation by 5.


5n + 5d = 300
5n + 10d = 500


Subtract to get -5d = -200, or d = 40.


There are 40 dimes, so there are 20 nickels.