SOLUTION: Gold is alloyed with different metals to make it hard enough to be used in jewelry. The amount of gold present in a gold alloy is measured in 24ths called karats. 24-karat gold is

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Question 943103: Gold is alloyed with different metals to make it hard enough to be used in jewelry. The amount of gold present in a gold alloy is measured in 24ths called karats. 24-karat gold is 2424 or 100% gold. Similarly, 18-karat gold is 1824 or 75% gold. How many ounces of 18-karat gold should be added to an amount of 12-karat gold to make 4 ounces of 14-karat gold?

Found 2 solutions by lwsshak3, josgarithmetic:
Answer by lwsshak3(11628) About Me  (Show Source):
You can put this solution on YOUR website!
Gold is alloyed with different metals to make it hard enough to be used in jewelry. The amount of gold present in a gold alloy is measured in 24ths called karats. 24-karat gold is 2424 or 100% gold. Similarly, 18-karat gold is 1824 or 75% gold. How many ounces of 18-karat gold should be added to an amount of 12-karat gold to make 4 ounces of 14-karat gold?
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let x=amt of 18 karat gold should be added
4-x=amt of 12 karat gold should be added
.75x+.50(4-x)=4*7/12
.75x+2-.50x=7/3
.25x=7/3-6/3=1/3
x=1/(3*.25)=1/.75=4/3
How many ounces of 18-karat gold should be added? 4/3

Answer by josgarithmetic(39620) About Me  (Show Source):
You can put this solution on YOUR website!
The exercise is no different than any of these:

Mixing two concentrations for known amount of mixture
http://www.algebra.com/my/Mixtures%3A-All-in-Symbols.lesson?content_action=show_dev

The concentration can simply be in unit, karats or numerator%2F24. You could also convert the karats into percents if you want that way. 12 karats would be 50% gold.