A btw..where I would suppose you got the 1/2 gal of oil in a gal of gasoline is 50:1 is thinking about percentages. A ratio is not a percentage. Well, you can figure a % from a ratio if you like, but keep the numbers straight. Mixing at 50:1 ratio doesn't give you a 50% by volume mixture. If you mix as per the original question, what you end up with is a 2:1 gasoline/oil ratio.
A 50% mixture would be equal parts gasoline/oil...1/2 of it oil (50%), 1/2 of it gasoline (the other 50%). Which would be...what? 1:1.
Yeah, a ratio rite is handy. Get a lid for it!
Consider that a quart of oil (one'a those US measured things) in five gallons of gasoline (another US measured thing) will give you a 40:1 gasoline/oil ratio.
***edit**
Word is pint...not quart.
I knew that!
My apologies.
Pointed out by farmerj. Thanks.