Question 217947
Let  x =  amt  added  (in  quarts)
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5 * 10% + x* 100% = (5+x) * 40%
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5*.1 +x*1 =(5+x) *.4
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.5 +x = 2 +.4x
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.6x = 1.5
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x= 2.5  quarts
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check
.1*5 +1*2.5 = 7.5 *.4
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.5 +2.5 = 3,,,,,,ok
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