Answer:
after 20 hours the cell will have divided 5 times
Step-by-step explanation:
this problem was easy because 20 is evenly divisible by 4. 20 ÷ 4 = 5
there's a short cheat-technique that i figured out where you don't need any formulas to solve this kind of problem. i attached a picture of what i did at the top of this answer. :)