SOLUTION: A chemist has 500 mL of a solution that is 60% acid. how much of a 30% solution must be added to make a solution that is 50% acid?

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Question 196704: A chemist has 500 mL of a solution that is 60% acid. how much of a 30% solution must be added to make a solution that is 50% acid?
Answer by josmiceli(19441) About Me  (Show Source):
You can put this solution on YOUR website!
given:
.6%2A500+=+300ml of acid
Let x= ml of solution to be added
.3x= ml of acid added
%28.6%2A500+%2B+.3x%29+%2F+%28500+%2B+x%29+=+.5
Multiply both sides by 500+%2B+x
300+%2B+.3x+=+.5%2A%28500+%2B+x%29
300+%2B+.3x+=+250+%2B+.5x
.2x+=+50
x+=+250 ml
250 ml of a 30% solution must be added
check:
%28.6%2A500+%2B+.3x%29+%2F+%28500+%2B+x%29+=+.5
%28.6%2A500+%2B+.3%2A250%29+%2F+%28500+%2B+250%29+=+.5
%28300+%2B+75%29+%2F+750+=+.5
375+=+.5%2A750
375+=+375
OK