In a laboratory, a certain culture of bacteria doubles every hour. If there are originally 20 bacteria in the culture, how many are present after 10 hours? 11 hours?

Answer 1

amount = 20 (2)^t
plug in t = 10, then t = 11

or do it the long way:

now -- 20
after 1 hour -- 40
after 2 hours -- 80
....