SOLUTION: A scientist has two solutions, which she has labeled Solution A and Solution B. Each contains salt. She knows that Solution A is 20% salt and Solution B is 45% salt. She wants to o

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Question 1168918: A scientist has two solutions, which she has labeled Solution A and Solution B. Each contains salt. She knows that Solution A is 20% salt and Solution B is 45% salt. She wants to obtain 140 ounces of a mixture that is 30% salt. How many ounces of each solution should she use?
Answer by Boreal(15235) About Me  (Show Source):
You can put this solution on YOUR website!
x oz of A for 0.20x pure salt
140-x oz of B for 63-0.45x pure salt
the total amount of pure salt desired is 140*0.3=42 oz.

sos 0.2x+63-0.45x=42
-0.25x=-21
x=84 oz of 20% one answer
140-x=60 oz of 45% the other answer
check
30% is 2/5 of the way from 20 to 45, so more of the 20% will be used.
84 oz is 3/5 of the total amount, weighting the final proportions towards the lesser concentration.