Answer
210 gallons
Work Step by Step
Given 1$\frac{3}{4}$ gal of herbicide is required to appy per acre of soybean
therefore we need to find how much gallon of herbicide is required for 120 acres =
1$\frac{3}{4}$ x 120 acres
= $\frac{7}{4}$ x 120
=210 gallons
