Question 988359
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x=gallons 5% to be added
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0.05x+0.01(90)=0.02(90+x)
0.05x+0.9=1.8+0.02x
0.03x=0.9
x=30
ANSWER: You should mix 30 gallons 5% acid solution.
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CHECK:
0.05(30)+0.01(90)=0.02(120)
1.5+0.9=2.4
2.4=2.4