SOLUTION: I am trying to clarify the notion of fresh versus salt water with a class. The ocean has a salinity level of 3.5%. If I have 8 ounces of fresh water, how much salt must I add to ac

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Question 1057724: I am trying to clarify the notion of fresh versus salt water with a class. The ocean has a salinity level of 3.5%. If I have 8 ounces of fresh water, how much salt must I add to achieve a solution with 3.5% salinity? I would like to create this mixture for the students.
Answer by josmiceli(19441) About Me  (Show Source):
You can put this solution on YOUR website!
Let +x+ = ounces of salt you need to add
+x+%2F+%28+8+%2B+x+%29+=+.035+
+x+=+.035%2A%28+8+%2B+x+%29+
+x+=+.28+%2B+.035x+
+.965x+=+.28+
+x+=+.2902+
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You need to add .2902 ounces of salt
( .29 or .3, whatever the limits of accuracy are )
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check:
+x+%2F+%28+8+%2B+x+%29+=+.035+
+.2902+%2F+%28+8+%2B+.2902+%29+=+.035+
+.2902+=+.035%2A8.2902+
+.2902+=+.29016+
close enough