If the directions specify adding 3 pounds of wettable powder (WP) per 100 gallons of water, how much WP is needed for a 450-gallon tank?

To determine the amount of wettable powder (WP) needed for a 450-gallon tank based on the provided instructions, you can set up the calculation as follows:

The directions specify using 3 pounds of WP for every 100 gallons of water. To find out how much WP is required for 450 gallons, you first need to calculate how many 100-gallon increments are in 450 gallons:

450 gallons ÷ 100 gallons = 4.5

This means that there are 4.5 increments of 100 gallons in a 450-gallon tank.

Next, you multiply the number of increments (4.5) by the amount of WP needed for each increment (3 pounds):

4.5 increments × 3 pounds/increment = 13.5 pounds

Thus, for a 450-gallon tank, you would need 13.5 pounds of wettable powder. This calculation confirms that option B is the correct answer. Using proportions in this way is very effective for scaling up or down to meet specific volume requirements when mixing pesticides or other chemicals.