Solution
10 oz of a 30 % gold alloy
20 oz of a 15 % gold alloy
[tex]\begin{gathered} 10.30\text{ \% + 20.15 \% = 30. x} \\ \frac{30}{100}\times10+\frac{15}{100}\times20=30x \end{gathered}[/tex][tex]\begin{gathered} 0.3(10)+0.15(20)=30x \\ 3+3=30x \\ 6=30x \\ x=\frac{6}{30} \\ x=0.2 \end{gathered}[/tex]0.2 to percentage
= 0.2 x 100 = 20 %
Hence the percent concentration = 20 %
Therefore the percent concentration of the resulting alloy = 20%
