<PRE><B>Question 999143</B>
You have 20 fl oz of a gas/oil mixture that is 2.5% oil. How much gas should you add to lower it to a 2% mix? 
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Equation:
oil + oil = oil
0.025*20 + 0*x = 0.02(20+x)
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Multiply thru by 1000 to get:
25*20 + 0 = 20*20+20x
20x = 5*20
x = 5 gallons (amt of pure gasoline to add)
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Cheers,
Stan H.
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