We have 33 gallons of flat paint and 57 gallons of high-gloss paint.
The total gallons sold is the sum of these two.
[tex]total\; gallons=33+57=90[/tex]The ratio of gallons of high-gloss to the total gallons sold is given by
[tex]ratio=\frac{high\; gloss\; gallons}{\; total\; gallons}=\frac{57}{90}[/tex]Simplify the ratio to the lowest terms by dividing with 3
[tex]ratio=\frac{57}{90}=\frac{19}{30}[/tex]Therefore, the ratio of gallons of high-gloss to the total gallons sold is 19/30