If you had a 1000 lb. cow, 25% would be ground beef. Therefore the cow would yield 1000 quarter lb. patties. 25% of the cow would be used for steaks and roast. The other 50% would consist of fat, hide and other no edible parts.
The term "proof" for alcohol was coined in the 16th. century in the British Navy when rum rations were given to sailors. Sometimes the officers would water the rum down and cheat the lower ranks. The sailors would take a sample of the rum at the beginning of the trip and place a pinch of gunpowder in it and light it up. If the Rum had a high percentage of alcohol it would burn, if there was too much water in the rum the alcohol would not ignite. Throughout the sea voyage "proof" would be taken of the rum.
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