To determine the combinations of coins that a restaurant cashier can give as change for $1 using no more than four coins, with the restriction that no coin is smaller than a nickel (5 cents) or bigger than a quarter (25 cents), we need to analyze the possible combinations of nickels (5 cents), dimes (10 cents), and quarters (25 cents).
Here are the relevant combinations that total $1 (100 cents):
-
Four Quarters:
- \(4 \times 25 = 100\) cents
- Combination: (25, 25, 25, 25)
-
One Quarter and Three Dimes:
- \(1 \times 25 + 3 \times 10 = 25 + 30 = 55\) cents
- Not valid.
-
Two Quarters and Two Dimes:
- \(2 \times 25 + 2 \times 10 = 50 + 20 = 70\) cents
- Not valid.
-
Three Quarters and One Nickel:
- \(3 \times 25 + 1 \times 5 = 75 + 5 = 80\) cents
- Not valid.
-
One Quarter, One Dime, and Two Nickels:
- \(1 \times 25 + 1 \times 10 + 2 \times 5 = 25 + 10 + 10 = 45\) cents
- Not valid.
After analyzing various combinations, the valid solutions are:
-
One quarter (25 cents) and three dimes (30 cents):
\(1 \times 25 + 3 \times 10 = 25 + 30 = 55\) cents- Combination: (25, 10, 10, 10)
-
Five dimes (10 cents):
\(10 \times 10 = 100\) cents- Combination: (10, 10, 10, 10)
So, it turns out there are only two valid combinations of coins that total to one dollar:
- Four Quarters: (25, 25, 25, 25)
- Five Dimes: (10, 10, 10, 10)
If you want to restrict to only combinations that sum up to $1, there are no other practical combinations within the constraints provided.