a)
\(\overline{A}=\dfrac{65.27+A_2.\left(100-27\right)}{100}=63,54\Rightarrow A_2=63\)
Chọn B
b)
\(\dfrac{108}{x_2}=\dfrac{27}{100-27}\)\(\Rightarrow x_2=292\)
Chọn C
c)
\(\%m_{\dfrac{Cu}{CuSO_4}}=\dfrac{27\%.65}{63,54+32,05+\left(15,999.4\right)}.100\%\approx10,99\%\)
Chọn D