You forgot an essential part of the question which is the date as to when you’re supposed to stop counting down. But I’ll give you a few dates to try and be of assistance...
(Day 1) 8000/2=4000
(Day 2) 4000/2=2000
(Day 3) 2000/2=1000
(Day 4) 1000/2=500
(Day 5) 500/2=250
And so forth like that
