SOLUTION: 40 cups of juice contains 5% juice. how many cups of pure juice is needed to make 10% juice

Algebra ->  Customizable Word Problem Solvers  -> Mixtures -> SOLUTION: 40 cups of juice contains 5% juice. how many cups of pure juice is needed to make 10% juice      Log On

Ad: Over 600 Algebra Word Problems at edhelper.com


    

Question 750537: 40 cups of juice contains 5% juice. how many cups of pure juice is needed to make 10% juice
Answer by josmiceli(19441) About Me  (Show Source):
You can put this solution on YOUR website!
You can assume that this is a juice and water mixture.
Let +x+ = the cups of pure juice to be added
+.05%2A40+=+2+ cups of pure juice in 5% mixture
----------------
+%28+2+%2B+x+%29+%2F+%28+40+%2B+x+%29+=+.1+
+2+%2B+x+=+.1%2A%28+40+%2B+x+%29+
+2+%2B+x+=+4+%2B+.1x+
+.9x+=+2+
+x+=+2.222+
2.222 cups of pure juice are needed
check:
+%28+2+%2B+x+%29+%2F+%28+40+%2B+x+%29+=+.1+
+%28+2+%2B+2.222+%29+%2F+%28+40+%2B+2.222+%29+=+.1+
+4.222+%2F+42.222+=+.1+
+.1+=+.1+
OK