The conversion rate for a gallon to quart is given as
[tex]1\text{ ga }\to4\text{ quart}[/tex]This means that to get the number of quarts in a given measure in gallons, we multiply the number by 4.
The question asks us to convert 15 gallons to quarts.
This can be calculated as
[tex]\begin{gathered} 15\times4 \\ =60\text{ quarts} \end{gathered}[/tex]Therefore,
[tex]15\text{ gal }\to60\text{ quarts}[/tex]