SOLUTION: A tropical fish store has 20 gallons of 15% salt solution. How many gallons of a 8% salt solution must be added to produce a 10% salt solution?

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Question 263523: A tropical fish store has 20 gallons of 15% salt solution. How many gallons of a 8% salt solution must be added to produce a 10% salt solution?
Answer by josmiceli(19441) About Me  (Show Source):
You can put this solution on YOUR website!
In words:
(amount of salt in final solution)/(total gallons in final solution) = 10%
Let x = gallons of 8% solution that need to be added
%28.15%2A20+%2B+.08x%29%2F%2820+%2B+x%29+=+.1
.15%2A20+%2B+.08x+=+.1%2A%2820+%2B+x%29
3+%2B+.08x+=+2+%2B+.1x
.02x+=+1
x+=+50
50 gallons of 8% solution need to be added
check answer:
%28.15%2A20+%2B+.08x%29%2F%2820+%2B+x%29+=+.1
%28.15%2A20+%2B+.08%2A50%29%2F%2820+%2B+50%29+=+.1
%283+%2B+4%29%2F%2820+%2B+50%29+=+.1
7%2F70+=+.1
.1+=+.1
OK