MATH HELP PLEASE 5 AND 6

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%

Asystem of equations has 1 solution. if 4x-y=5 is one of the equations , which could be the other equation ?

The probability that a tutor will see 0, 1, 2, 3, or 4 students is given below determine the probability distribution's missing value.