Final answer:
The number of bacteria after 8 hours, with a doubling time of 20 minutes, can be calculated by multiplying the starting population by 2 raised to the power of the number of doubling cycles.
Step-by-step explanation:
The question asks how many bacteria will be present after 8 hours if they divide every 20 minutes. To solve this, we need to find the number of doubling cycles that will occur in 8 hours by dividing the total time in minutes (480 minutes) by the doubling time (20 minutes). This gives us 24 doubling cycles. Since each doubling cycle results in 2 times the previous population, we can calculate the final number of bacteria by multiplying the starting population (5 bacteria) by 2 raised to the power of the number of doubling cycles (24). This gives us a final population of 5 * 2^24 bacteria after 8 hours.