from his paper route, andy collected $5.55 in nickels and dimes. The number of nickels was 6 more than the number of dimes. How many nickels and dimes were there?

2 answers

n = d+6
5 n + 10 d = 555 cents

5(d+6) + 10 d = 555
5 d + 30 + 10 d = 555
etc
add up the values
If there were x dimes, then
10x + 5(x+6) = 555