Staff from the school newspaper is taking a poll to find out how students in the school are going to vote in the upcoming election for class president. which group would best represent a sample population? every tenth student staying after school. every tenth student in the library at lunch. every tenth student in the main hallway between class. every tenth student in the student section at the school football game.

Polling every tenth student in the main hallway between class would provide the most representative sample because most or all students transit this hallway whereas the other options would disproportionately favor certain subsets of the student body. For example, polling every tenth student in the library at lunch would give a result that favors the views of students who frequent the library or like to study and polling students at the football game would yield results that favor those who prefer sports.

3cm and 6 and 9 cm that a possibility of that question

It is the top one. the answer is -7. that is smallest