Number 12 please 12 only
640 cells. add together 5 plus 5 you get 10, 10 plus 10 you get 20
So @ 12 : there are 5then @1 : there are 10then @ 2: there are 20then @3 :there are 40then @4: 80then @5: 160then @6 320then @7 pm; 640 cells.Its basically multiplibg by two every hour/ doubling.There would be 640 cells by 7pm