Answer:
a 18
Explanation:
To determine how many students can sit at the tables, we need to multiply the number of tables by the number of students that can sit at each table.
Number of students that can sit at tables = Number of tables × Number of students per table
Number of students that can sit at tables = 9 tables × 2 students per table
Number of students that can sit at tables = 18
Therefore, 18 students can sit down at the tables.