With a confidence level of .95 and a confident interval of 5 and a

population of 20,000 what is the sample size?

With a confidence level of .99 and a confident interval of 5 and a
population of 20,000 what is the sample size?

Finally, using the sample size for question 1 and 2 and a response
distribution of 50% (i.e., percentage box) what is the confidence
interval for questions 1 and 2.

If you had the time to explain how you figured those out, that would help me tremendously :~), I have been trying to figure it out, but to no avail....