To formulate a system of linear equations based on the situation described for Ava's bills, we can define two variables:
Let:
- \( x \) = the number of five-dollar bills
- \( y \) = the number of twenty-dollar bills
From the information given, we can create the following equations:
-
The total number of bills: \[ x + y = 35 \]
-
The total value of the bills: \[ 5x + 20y = 415 \]
Now we can solve this system of equations.
First, we can simplify the second equation by dividing every term by 5: \[ x + 4y = 83 \]
Now we have the system of equations:
- \( x + y = 35 \)
- \( x + 4y = 83 \)
Next, we can use the first equation to substitute \( x \) in the second equation: From \( x + y = 35 \), we can express \( x \) as: \[ x = 35 - y \]
Now, substituting this expression for \( x \) into the second equation: \[ (35 - y) + 4y = 83 \] \[ 35 - y + 4y = 83 \] \[ 35 + 3y = 83 \] \[ 3y = 83 - 35 \] \[ 3y = 48 \] \[ y = 16 \]
Now that we have \( y \), we can find \( x \): \[ x = 35 - y = 35 - 16 = 19 \]
So, Ava has:
- \( x = 19 \) five-dollar bills
- \( y = 16 \) twenty-dollar bills
Thus, the solution is: 19 five-dollar bills and 16 twenty-dollar bills.
Comparing this with the available responses, the correct answer is: 19 five-dollar bills and 16 twenty-dollar bills.