a,
Gọi a là mol Mg, b là mol Zn
BTNT, n kim loại= n muối \(\rightarrow\left\{{}\begin{matrix}24x+65b=11,4\\95a+136b=30,57\end{matrix}\right.\rightarrow\left\{{}\begin{matrix}a=0,15\\b=0,12\end{matrix}\right.\)
\(m_{Mg}=\frac{0,15}{24}=3,6\left(g\right)\)
\(m_{zn}=\frac{0,12}{65}=7,8\left(g\right)\)
b,
BTNT, \(n_{HCl}=2n_{MgCl2}+2n_{ZnCl2}=0,54\left(mol\right)\)
\(\rightarrow m_{dd_{HCl}}=\frac{0,54.36,5.100}{100}197,1\left(g\right)\)