Option 2 would be biased. Asking people participating in a walkathon means you are asking people that are already volunteering. To get a non-biased sample, you have to be sure that you are including people that are not guaranteed to be volunteers; you don't have that in this situation.
your answer would be 9 fish are left in the tank
The total area is 84m.
Work is in the image, feel free to ask if you don’t understand it.
Hope this helped :)
Step-by-step explanation:
She made a sign error when multiplying and should have had 256 as a final answer.