A city park employee collected 600 cents in nickels, dimes and quarters at the bottom of a wishing well. There were 10 nickels and a combined total of 25 dimes and quarters. How many dimes and quarters were at the bottom of the well? I know the answer but need help with what the equation is to get the answer. Thank you

600 = 5 n + 10 d + 25 q

n = 10
d + q = 25

600 = 50 + 10 d + 25 q
or
550 = 10 d + 25 q
or
110 = 2 d + 5 q

so
2 d + 5 q = 110
2 d + 2 q = 50
----------------
3 q = 60
q = 20
you take it from there.