3(n + 2)

i need and explination on why this is correct and why its not 3n + 2

34 cup. a serving of vegetable soup is 23 cup. the restaurant sold 20 servings of chicken noodle soup and 18 servings of vegetable soup. how many more cups of chicken noodle soup did they sell than cups of vegetable soup?

At a book fair, joe bought 24 books at 3 for $5 and had $2 left. how much money did he have at first?

Michael split a rope that was 28 inches long into 5 equal parts. brenden split a rope that was 30 inches long into 6 equal parts. which boy's rope was cut into longer pieces?