Answer:
480 hours of volunteering was done by 128 employees in a 1 week.
3.75 hours of volunteering was done by each employee per week
Explanation:
Number of employees volunteer in 12480 hours = 128
Number of weeks of volunteered by 128 employees = 26 weeks
Number of hours of volunteered by 128 employees = 12480 hours
12480 hours of volunteering was done by 128 employees in 26 weeks:
Volunteering done by 128 employees hour per week :

128 employees volunteered = 480 hours/week
480 hours of volunteering was done by 128 employees in a 1 week.
Then 1 employee volunteered is:

3.75 hours of volunteering was done by each employee per week