SOLUTION: After 40 pounds of water had been evaporated from a solution of salt and water that was 10% salt, the solution that resulted was 15% salt. Find the number of pounds in the original

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Question 1058745: After 40 pounds of water had been evaporated from a solution of salt and water that was 10% salt, the solution that resulted was 15% salt. Find the number of pounds in the original solution.
Found 4 solutions by josmiceli, addingup, ikleyn, MathTherapy:
Answer by josmiceli(19441) About Me  (Show Source):
You can put this solution on YOUR website!
Let +x+ = pounds of original solution
+.1x+ = pounds of salt in original solution
-------------------------------------------
The amount of salt in solution does not change
+.1x+%2F+%28+x+-+40+%29+=+.15+
+.1x+=+.15%2A%28+x++-+40+%29+
+.1x+=+.15x+-+6+
+.05x+=+6+
+x+=+120+
------------------------------------
The original solution was 120 pounds
------------------------------------
check:
+.1%2A120+=+12+ pounds of salt
and
+12+%2F+%28+120+-+40+%29+=+12%2F80+
+12%2F80+=+.15+
OK

Answer by addingup(3677) About Me  (Show Source):
You can put this solution on YOUR website!
0.1x-40 = 0.15
0.1x = 40.15
x = 401.5

Answer by ikleyn(52855) About Me  (Show Source):
You can put this solution on YOUR website!
.
There is entire bunch of lessons covering various types of mixture problems
    - Mixture problems
    - More Mixture problems
    - Solving typical word problems on mixtures for solutions
    - Word problems on mixtures for antifreeze solutions
    - Word problems on mixtures for alloys
    - Typical word problems on mixtures from the archive
in this site.

Read them and become an expert in solution the mixture word problems.

Also, you have this free of charge online textbook in ALGEBRA-I in this site
    - ALGEBRA-I - YOUR ONLINE TEXTBOOK.

The referred lessons are the part of this textbook under the topic "Mixture problems".

The textbook contains many other solved word problems, as well as many other interesting and useful things.


Answer by MathTherapy(10555) About Me  (Show Source):
You can put this solution on YOUR website!
After 40 pounds of water had been evaporated from a solution of salt and water that was 10% salt, the solution that resulted was 15% salt. Find the number of pounds in the original solution. 
Original mixture was: highlight_green%28matrix%281%2C2%2C+120%2C+lbs%29%29