How to write this problem as an Equation

Shane has 4 more dimes than quarters and 7 fewer nickels than dimes. He has 28 coins in all. How many quarters does Shane have?

So Shane has 'd' dimes

He has 4 more dimes than quarters 'q', so q = d - 4

7 fewer nickels 'n' than dimes, so n = d - 7

So d + q + n = 28

d + d - 4 + d - 7 = 28

3d = 39

d = 13

q = d - 4

q = 13 - 4 = 9 quarters.

Notice that I used a different approach from the first time I solved it but arrived at the same answer.

D-4+D+D-7 = 28
D = 13 dimes
9 Quarters
6 Nickels
Answer 9