Final answer:
To determine how many quarts are in a gallon, we use the conversion that 1 gallon is equal to 4 quarts. Therefore, Melissa needs to buy 4 quarts of milk to equal one gallon.
Step-by-step explanation:
The question you have asked regarding the number of quarts in a gallon falls under the subject of Mathematics, more specifically, it is related to measurement conversion which is typically taught in middle school. In order to find out how many quarts of milk Melissa needs to buy to equal a gallon, we need to be aware of the conversion between gallons and quarts.
Everyday measurement units are often defined as fractions or multiples of other units. For instance, milk is commonly packaged in containers of different sizes and the conversion between these sizes is straightforward:
- 1 gallon is equal to 4 quarts
- 1 quart is equal to 0.25 gallon
- 1 pint is equal to 0.5 quart
Since Melissa's mother asked her to buy a gallon of milk and the store has only quarts, we then use the unit equivalence that 1 gallon is equal to 4 quarts. Therefore, Melissa should buy 4 quarts of milk to have the equivalent of one gallon.