I believe that c = 9.2425 m
Answer:
4 stations
Step-by-step explanation:
If we need to be at least 98% certain that an enemy plane flying over will be detected by at least one station, we must ensure that there is at most a 2% chance that no radar stations detect the plane.
The probability that a single radar station does not detect the plane is 0.35.
For n radar stations:

Rounding up to the next whole station, at least 4 stations are needed.
Well if 50= 100 % then 250 percent =150. (if you meant 25% then 25)
A entomologist, they study the spread of insects