Which word phrase give used to represent algebraic expression 4(21 + n)?

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%

Ijust need these 2 questions answered (the second pic is just confirmation i'm not confident in that answer)

The owner of the plant nursery where you were tells you to fill 350 ml bottles from a 30 l from a fertilizer