Birdseed costs $\$ 0.69$ a pound and sunflower seeds cost $\$ 0.99$ a pound. Angela Leinenbachs' pet store wishes to make a 50 -pound mixture of birdseed and sunflower seeds that sells for $\$ 0.79$ per a pound. How many pounds of each type of seed should she use? How many pounds of birdseed should Angela use? pounds (Type an integer, proper fraction, or mixed number.)

Step 1 ：Let the amount of birdseed be \(x\) pounds and the amount of sunflower seeds be \(y\) pounds. We have the following equations:

Step 2 ：1. \(x + y = 50\) (total weight of the mixture)

Step 3 ：2. \(0.69x + 0.99y = 0.79 * 50\) (total cost of the mixture)

Step 4 ：Solve the system of equations to find the values of \(x\) and \(y\):

Step 5 ：\(x = 50 - y\)

Step 6 ：Substitute \(x\) in the second equation:

Step 7 ：\(0.69(50 - y) + 0.99y = 39.5\)

Step 8 ：Solve for \(y\):

Step 9 ：\(y \approx 16.67\)

Step 10 ：Substitute \(y\) back into the equation for \(x\):

Step 11 ：\(x = 50 - 16.67\)

Step 12 ：\(x \approx 33.33\)

Step 13 ：\(\boxed{x \approx 33.33}\) pounds of birdseed should be used.