Final answer:
To determine the number of nickels in the piggy bank, we can set up a equation using the given information. By solving the equation, we can find the value of x, which represents the number of quarters. Substituting this value back into the expression x/2 + 8 will give us the number of nickels.
Step-by-step explanation:
Let's say the number of quarters in the piggy bank is x.
The number of nickels is 8 more than half the number of quarters, so it is x/2 + 8.
The value of the coins in the piggy bank is $21.85, which can be written as 2185 cents.
The value of each quarter is 25 cents, so the total value of quarters is 25x cents.
The value of each nickel is 5 cents, so the total value of nickels is 5(x/2 + 8) cents.
Equating the total value of quarters and nickels to 2185 cents, we get the equation:
25x + 5(x/2 + 8) = 2185
Solving this equation will give us the value of x, which represents the number of quarters. Once we find the value of x, we can find the number of nickels by substituting it back into the expression x/2 + 8.