Perform the operation: 3 gal, 1 qt. - 1 gal, 3 qt.

5 gal

4 gal, 4 qt.

1 gal. 2 qt.

1 gal

Ah, college mathematics.

We must remember there are four quarts per gallon. Let's convert everything to gallons:

3 / frac 1 4 - 1 / frac 3 4 = / frac{13}{4} - / frac{7}{4} = / frac{6}{4} = 1 / frac 2 4

We don't reduce because it's easy to see that's 1 gallon, 2 quarts, third choice.

1 gal. 2 qt.