How many pounds of 25 percent WP must you add to 100 gallons of water to achieve a 1 percent active ingredient mixture?

To determine how many pounds of a 25 percent wettable powder (WP) are needed to achieve a 1 percent active ingredient mixture in 100 gallons of water, we start by calculating the total amount of active ingredient desired in that water volume.

First, calculate the total weight of the 1 percent solution in 100 gallons of water. Since 1 percent of 100 gallons equals 1 gallon, and knowing that 1 gallon of water weighs about 8.34 pounds, the total weight of the water is:

100 gallons x 8.34 pounds/gallon = 834 pounds.

Next, 1 percent of this total weight is calculated:

1 percent of 834 pounds = 0.01 x 834 pounds = 8.34 pounds of active ingredient needed.

Since the wettable powder is 25 percent active ingredient, we need to find out how much of the WP is required to obtain 8.34 pounds of active ingredient. This can be calculated using the formula:

Total weight of WP needed = Active ingredient needed / Concentration of WP.

Substituting in the known values:

Total weight of WP needed = 8.34 pounds / 0.25 = 33.36 pounds.

Rounding