SOLUTION: how much pure alcohol should be added to 600ml,15% alcohol solution to make it contain 25% alcohol?

Algebra ->  Coordinate Systems and Linear Equations  -> Linear Equations and Systems Word Problems -> SOLUTION: how much pure alcohol should be added to 600ml,15% alcohol solution to make it contain 25% alcohol?      Log On


   

Question 753146: how much pure alcohol should be added to 600ml,15% alcohol solution to make it contain 25% alcohol?
Answer by josmiceli(19441) About Me  (Show Source):
You can put this solution on YOUR website!
Let +x+ = ml of pure alcohol to be added
+.15%2A600+=+90+ ml of alcohol in 15% solution
-------------
+%28+x+%2B+90+%29+%2F+%28+x+%2B+600+%29+=+.25+
+x+%2B+90+=+.25%2A%28+x+%2B+600+%29+
+x+%2B+90+=+.25x+%2B+150+
+.75x+=+60+
+x+=+80+
80 ml of pure alcohol should be be added
check:
+%28+x+%2B+90+%29+%2F+%28+x+%2B+600+%29+=+.25+
+%28+80+%2B+90+%29+%2F+%28+80+%2B+600+%29+=+.25+
+170+%2F+680+=+.25+
+170+=+.25%2A680+
+170+=+170+
OK