Answer: 1.26 * 10^22 electrons
Explanation: In order to explain this problem we have to use the following relationship:
the charger delivers -0.75C/s ; during 45 min it will deliver
-0.75*45*60=2025C
so considering that the electron charge is -1.6 *10^-19 C
We have:
-2025 C/-1.6 *10^-19 C 1.26 * 10^22 electrons