The answers are 15 guests, 7 tables, 24 guests, and 10 tables respectively.
Step-by-step explanation:
2 tables ⇒ 6 guests
1 table ⇒ 6/2 = 3 guests
5 tables = 5 × 3 = 15 guests
Number of tables = 21/3 = 7 tables
Number of guests = 8 × 3 = 24 guests
Number of tables = 30/3 = 10 tables