SOLUTION: In the chemistry lab, Efren mixed salt and water to produced 4 liters of a 50% solution. He wanted to know how many liters he will have to evaporate so that he gets a 75% solution?

Algebra ->  Customizable Word Problem Solvers  -> Mixtures -> SOLUTION: In the chemistry lab, Efren mixed salt and water to produced 4 liters of a 50% solution. He wanted to know how many liters he will have to evaporate so that he gets a 75% solution?      Log On

Ad: Over 600 Algebra Word Problems at edhelper.com


    

Question 1005197: In the chemistry lab, Efren mixed salt and water to produced 4 liters of a 50% solution. He wanted to know how many liters he will have to evaporate so that he gets a 75% solution?
Answer by josmiceli(19441) About Me  (Show Source):
You can put this solution on YOUR website!
+.5%2A4+=+2+ liters of water to start with
Let +x+ liters = amount to be evaporated
-------------------------------------
You end up with the same liters of salt you started with ( 2 liters )
+2+%2F+%28+4+-+x+%29+=+.75+
+2+=+.75%2A%28+4+-+x+%29+
+2+=+3+-+.75x+
+.75x+=+1+
+x+=+1.333+
--------------
1 and 1/3 liters must be evaporated
--------------
check:
+2+%2F+%28+4+-+x+%29+=+.75+
+2+%2F+%28+4+-+4%2F3++%29+=+.75+
+2+%2F+%28+8%2F3+%29+=+3%2F4+
+6%2F8+=+3%2F4+
+3%2F4+=+3%2F4+
OK