Question 800405
What quantity of 80 per cent acid solution must be mixed with a 20 per cent solution to produce 120 mL of a 50 per cent solution? 
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Equation:
acid + acid = acid
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0.80x + 0.20(120-x) = 0.50*120
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80x + 20*120 - 20x = 50*120
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60x = 30*120
x = 60 mL (amt. of 80% solution needed)
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120-60 = 60 mL (amt. of 20% solution needed)
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Cheers,
Stan H.
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