If an aircraft treats 14 acres with a volume of 1.5 pints per acre, how many pints are needed for the spray tank?

To determine the total volume of spray needed, you can use the formula for the total volume, which is the area being treated multiplied by the application rate per acre. In this scenario, the area being treated is 14 acres, and the application rate is 1.5 pints per acre.

By calculating:

Total volume = Area x Application rate

Total volume = 14 acres x 1.5 pints per acre

Total volume = 21 pints

This calculation shows that to adequately treat 14 acres with the specified application rate, you will require a total of 21 pints of spray solution in the tank. Therefore, the correct answer is indeed 21 pints.