None. That's a hardware problem.
Change.
A $100 bill makes change
Twenty. 1 to hold the bulb 2 to turn the ladder and 17 to be on the guest list.
None. They aren't about to change a bulb when flipping a switch has worked for 15 years.
A developing country
Because OCT 31 == DEC 25
None. That's a hardware problem but have you tried turning it on and off again