Answer:
30 quarts costs $37.50
Explanation:
We can use proportions to solve this problem. Put the cost over the size. The trick of this problem is the units in the denominator have to be the same
Lets change gallons to quarts.
1 gallon = 4 quarts
5 gallons * 4 quarts/1 gallon = 20 quarts
$25 x dollars
---------- = -----------
20 quarts 30 quarts
Using cross products
25*30 = 20x
Divide by 20
25*30/20 = 20/x
37.5 = x
30 quarts costs $37.50