Let's start the problem by assigning variables to the unknown quantities. Let's call the number of nickels "n", the number of dimes "d", and the number of quarters "q".
From the problem, we know:
- q = n - 4 (there are four fewer quarters than nickels)
- d + q = q + 3 (there are 3 more dimes than quarters)
- The total value of the collection is $6.5
To convert everything to cents, we can multiply everything by 100:
- 5n + 10d + 25q = 650 (total value in cents)
Now, we can use the first two equations to get rid of one variable.
Substituting q in terms of n:
- q = n - 4
Substituting q in terms of d:
- q = d + 3
Since both equations are equal to q, they must be