Answer: 109 nickels and 89 dimes
Steps:
198 coins in total and the amount of nickels are 20 more than dimes. (n for the amount of nickels, d for the amount of dimes):
n = 20 + d
n + d = 198
Take the first equation and make it into:
n - d = 20
Now let’s add both equations together:
n + d + n - d = 218
2n = 218
n = 109
109 - 20 = d
d = 89
