Question 389953
Santa's fish tank contains 200 gallons of sea water. The sea water is 7.5% salt. How many gallons of fresh water must be added to the tank so that the mixture only contains 7% salt? 
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Equation:
salt + salt = salt
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0.075*200 + 0*x = 0.07(200+x)
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Multiply thru by 1000 to get:
75*200 + 0 = 70*200 + 70x
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70x = 5*200
x = 14.29 gallons (amount of water that must be added)
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Cheers,
Stan H.
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