SOLUTION: Brianna has an alloy containing 10% gold. Emma has 1/2 ounces of an alloy containing 71% gold. They combined their alloys to make an alloy with 46 3/5% gold. Gold is worth $209.31

Algebra ->  Customizable Word Problem Solvers  -> Mixtures -> SOLUTION: Brianna has an alloy containing 10% gold. Emma has 1/2 ounces of an alloy containing 71% gold. They combined their alloys to make an alloy with 46 3/5% gold. Gold is worth $209.31      Log On

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Question 323122: Brianna has an alloy containing 10% gold. Emma has 1/2 ounces of an alloy
containing 71% gold. They combined their alloys to make an alloy with 46 3/5% gold. Gold is worth $209.31 an ounce at the current market value. Brianna estimated the value of the new alloy to be $81.28 an ounce. How many ounces of Brianna's alloy were used?

Answer by galactus(183) About Me  (Show Source):
You can put this solution on YOUR website!
Let x=amount of alloy Brianna is using.
The amount of gold is then
.10x+.71(.5)=.466(.5+x)
Solve for x to find how much alloy Brianna used.
Since .10x+.71(.5) is the amount of gold in the alloys, plugging this value into .10x+.71(.5) and multiplying by 209.31 should give 81.28.