[tex]\huge\color{pink}\boxed{\colorbox{black}{Answer ☘}}[/tex]
12 mC
We are given that...
[tex]C_{1} = 4mF \\ V_{1} = 50v \\ C_{2} = 6mF \\ V_{2} = 30v \\ \\ we've \: to \: find \: the \: final \: charge \: on \: the \: 6mF \\capacitor \:- \\ \\ we \: know \: that ,\: \\ Q = CV \\ \\ using \: the \: formula \: \\ Q_{1} = 4 \times 50 = 200mC \\ Q_{2} = 6 \times 30 = 180mC \\ \\ total \: charge , \: Q_{1} - Q_{2} = 200 - 180 = 20mC \\ \\ let \: V \: be \: the \: final \: potential \: \\ 4V + 6V = 20mC\\ 10V = 20mC \\ V = \frac{20}{10} = 2V \\ final \: charge \: Q = CV = 6 \times 2 = 12mC[/tex]
therefore,
hope helpful~