You do 600 divided by 2700 and you end up with 22/100 or 0.22 as a decimal. So if 0.22 or 22/100 are venimous then 78/100 or 0.78 are non venimous. I understand its a bit confusing and i can simplify it for you but still I hope this helps :)
Answer:
Standard deviation 46.3
Step-by-step explanation:
A 28% of the distribution is equivalent to a z score of -0.5828, you can use a z table to find that.
Z score is calculated as follows:

x is the number being evaluated
μ is the mean
σ is the standard deviation
And it is used to calculate how many standard deviations you are from the mean of the sample.
Replacing with the known information you can calculate the standard deviation:

Answer would be A) -410 feet because you just add or subtract when needed that easy hope it helps! :p
The answer would be C! Correct me if I’m wrong guys