



 
According to Wikipedia (http://en.wikipedia.org/wiki/Gallon) a U.S. Liquid Gallon is 128 fluid ounces. This means that you would need SIX 20 fluid ounce bottles, PLUS another 8 fluid ounces, to make one U.S. Liquid Gallon. (128/20 = 6 remainder 8) If you only have FOUR 20 fluid ounce bottles, you will have 80 fluid ounces (4*20=80), which is not enough to make a U.S. Liquid Gallon. If you are talking about some other kind of gallon (such as a U.S. Dry Gallon or an Imperial (UK) Gallon) then this might not apply. However, I know of no "gallon" which is equal to 80 oz. Hope this helps. Gabriel  


Math Central is supported by the University of Regina and The Pacific Institute for the Mathematical Sciences. 