Question 608429
    A chemist has 500 liters of a 60% solution of silver nitrate. How many liters of a 30% silver nitrate solution should be added to obtain a 50% solution.
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Let x = amount (liters) of 30% silver nitrate solution added
then
.30x + .60(500) = .50(500+x)
.30x + 300 = 250+.50x
300 = 250+.20x
50 = .20x
50/.20 = x
250 liters = x