According to the values
given in your question,
solution is as follows:
Charge on each atom=29 C
Total charge on the copper ball=29×4×10=1160 C
Thus,the number of electrons on the copper ball=1160(Since it is initially uncharged)
Number of electrons in 9.6 C
=9.6÷(1.6×10^−19)
=6×10^19
This is the number of electrons to be removed.
So, the fraction of electrons to be removed is given by
(6×10^19)÷1160
=(6000×10^16)÷(1160)
=5.17×10^16
Like if satisfied