Question 204884
A collection of 36 coins consists of nickels, dimes, and quarters.
n + d + q = 36
:
 There are three fewer quarters than nickels
n = q + 3
;
 and six more dimes than quarters.
d = q + 6
:
How many of each kind of coin are there?
Substitute for n and q in the 1st equation:
(q+3) + (q+6) + q = 36
3q + 9 = 36
3q = 36 - 9
q = {{{27/3}}}
q = 9 quarters
;
I'll let you find the number nickels and dimes