How much active ingredient is contained in a 20 lb bag of a 25W formulation?

To determine the amount of active ingredient (AI) in a 20 lb bag of a 25W formulation, you need to understand what the "25W" designation means. In this context, "25W" indicates that the formulation contains 25% active ingredient by weight.

To calculate the amount of AI in the bag, you take 25% of the total weight of the product. So, you can perform the calculation as follows:

1. Convert the percentage to a decimal: 25% is 0.25.

2. Multiply this decimal by the total weight of the bag:

( 0.25 \times 20 \text{ lbs} = 5 \text{ lbs of AI} ).

This calculation shows that a 20 lb bag of a 25W formulation contains 5 lbs of active ingredient. Therefore, the correct answer is aligned with the understanding of how active ingredients are calculated based on the given formulation percentage.