The atomic mass of the copper is
[tex]63\times69.17\text{ \% + 65}\times30.83\text{ \%}[/tex]solve the above expression
[tex]63\times\frac{69.17}{100}+65\times\frac{30.83}{100}[/tex][tex]63\times\frac{6917}{10000}+65\times\frac{3083}{10000}[/tex][tex]46.35+20.03=66.38[/tex]So the atomic weight of the mixture is 66.36 .
