Can someone give me an albgebraic real world example that’s original

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%

Maria walks a round trip of 0.75 mile to school every day.how many miles will she walk in 4.5 days

10% of 1,900,000. show me how you got the answer