Each electron has a charge of [tex]e=-1.6 \cdot 10^{-19} C[/tex]
The initial charge of the object is [tex]Q_i = -2.0 \mu C=-2.0 \cdot 10^{-6} C[/tex]
The final charge of the object is [tex]Q_f = +3.0 \mu C=+3.0 \cdot 10^{-6}C[/tex]
So the change in charge of the object is
[tex]\Delta Q = Q_i - Q_f =-2.0 \cdot 10^{-6} C-(3 \cdot 10^{-6} C)=-5.0 \cdot 10^{-6} C[/tex]
So, the number of electrons removed from the object is
[tex]N=\frac{\Delta Q}{e}=\frac{-5.0 \cdot 10^{-6} C}{-1.6 \cdot 10^{-19}C}=3.13 \cdot 10^{13}[/tex]
