Let's begin by listing out the information given to us:
Let nickel be represented as n, and dimes as d
Melanie has $1.80 worth of nickels and dimes:
She has 12 more nickels than dimes:
The point of intersection of the graph is (0.6, 1.74). Therefore, the number of nickels is 0.6 while the number of dimes is 1.74