To represent the total weight of sunflower seeds and pumpkin seeds, you can write the equation as follows:
\[ s + p = 20 \]
Where:
- \( s \) represents the number of pounds of sunflower seeds.
- \( p \) represents the number of pounds of pumpkin seeds.
- The total weight of the seeds is 20 pounds.
So, the equation \( s + p = 20 \) shows that the sum of the pounds of sunflower seeds and pumpkin seeds equals 20 pounds.