<PRE><B>Question 1023360</B>
We need a total of 50
Let X be the amount of 18 karat 
So (50-X) is the amount of 12 karat gold

{{{((50-X)(0.50) + X(0.75) )/50 = 58/100}}}
{{{(25-0.50X + 0.75X )/50 = 58/100}}}
{{{(25 + 0.25X )/50 = 58/100}}}
Do the cross products
{{{58*50 = 100(25+0.25X)}}}
2900 = 2500 + 25X
add -2500 to each side
400 = 25X
divide each side by 25
16 = X , the amount of 18K ( 75% )
(50 - X ) = (50 - 16) = 34 , the amount of 12K (50%)
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