Answer:
32 days
Explanation:
First, you must find out how much the organisms grew:
180 - 120 = 60
Then, you must find how many organisms grew in a day:
60 ÷ 6 = 10
So, we know that in one day 10 organisms grow. But how many more days until the species reaches 500?
500 - 180 = 320
So, 320 organisms have to grow to become 500. Now, we need to find how many days it will take for the population to grow to 320.
320 ÷ 10 = 32
So it will take 32 days until the population of the species is 500.
Hope this helps you out ; )