SOLUTION: A goldsmith has two alloys that are different purities of gold. The first is three-fourths pure and the second is five-twelfths pure. How many ounces of each should be melted and m

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Question 309635: A goldsmith has two alloys that are different purities of gold. The first is three-fourths pure and the second is five-twelfths pure. How many ounces of each should be melted and mixed in order to obtain a 6oz mixture that is two-thirds pure?
Answer by stanbon(75887) (Show Source):
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A goldsmith has two alloys that are different purities of gold. The first is three-fourths pure and the second is five-twelfths pure. How many ounces of each should be melted and mixed in order to obtain a 6oz mixture that is two-thirds pure?
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Equation:
gold + gold = gold
(3/4)x + (5/12)(6-x) = (2/3)6
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Multiply thru by 12 to get:
9x + 5(6-x) = 8*6
9x + 5*6 - 5x = 8*6
4x = 3*6
x = 4.5 oz (amt. of (3/4)th alloy needed)
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6-x = 1.5 oz (amt of 5/12th alloy needed)
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Cheers,
Stan H.
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