Answer: 25 pounds.
Explanation:
Let x represent the number of pounds of seeds that worth 80¢.
Let y represent the number of pounds of seeds that worth 50¢.
Based on the information given in the problem, you can set up the following system of equations:

Apply the method of elimination:
- Multiply the first equation by -50
- Add both equations.
- Solve for x.
Then:

Therefore, the answer is: 25 pounds of 80 cent seed should be use.