SOLUTION: How much pure acid should be mixed with 5 gallons of a 40% acid solution in order to get a 90% acid solution?

Algebra ->  Test -> SOLUTION: How much pure acid should be mixed with 5 gallons of a 40% acid solution in order to get a 90% acid solution?      Log On


   



Question 752579: How much pure acid should be mixed with 5 gallons of a 40% acid solution in order to get a 90% acid solution?
Answer by josmiceli(19441) About Me  (Show Source):
You can put this solution on YOUR website!
Let +x+ = gallons of pure acid to be added
+.4%2A5+=+2+ gallons of acid in 40% solution
---------------
+%28+2+%2B+x+%29+%2F+%28+5+%2B+x+%29+=+.9+
+2+%2B+x+=+.9%2A%28+5+%2B+x+%29+
+2+%2B+x+=+4.5+%2B+.9x+
+.1x+=+2.5+
+x+=+25+
25 gallons of pure acid must be added
check:
+%28+2+%2B+x+%29+%2F+%28+5+%2B+x+%29+=+.9+
+%28+2+%2B+25+%29+%2F+%28+5+%2B+25+%29+=+.9+
+27+%2F+30+=+.9+
+27+=+.9%2A30+
+27+=+27+
OK