In the equation minus m over 20 +4=7 what is first step to solve

Which choice represents the sample space ,s for this event

Acredit card advertises an annual interest rate of 23%. what is the equivalent monthly interest rate?

The first-serve percentage of a tennis player in a match is normally distributed with a standard deviation of 4.3%. if a sample of 15 random matches of the player is taken, the mean first-serve percentage is found to be 26.4%. what is the margin of error of the sample mean? a. 0.086% b. 0.533% c. 1.11% d. 2.22%