50:1 means 50 parts gasoline to one part of oil by volume.
50 gallons gasoline to one gallon of oil.
or 50 fluid ounces gas to one fluid ounce oil.
or 50 pints of gas to one pint of oil... it's all the same 50:1 ratio
a gallon is 128 ounces.
128 divided by 50 = 2.56.
So, 50:1 means one gallon of gas to 2.5 ounces of oil.
one liter of gasoline = 1,000 ml.
1,000 divided by 50 = 20
So, 50:1 means you'd add 20 ml to each liter of gasoline.