Help me with some gas/oil ratios

[Homerboy]

Say I have 1 US Gallon of gasoline that is currently at a 32:1 oil mixture
I need to convert that to 50:1 oil mixture.
How much do I add?

 

[drinkmorejava]

add 19/33 gal gas -> 73.7oz


1/33 (current amount of oil)*51 (total number of parts in new ratio) -32/33 (amount of gas already have)->19/33 gal