(simple aggregation without grouping) USE WHERE to express joins between tables and write SQL queries for problems 1-6 based on the 4 tables below.

**A presentation consists of a single speaker appearing in a single session.

TABLES:

1. The total combined seating capacity of all rooms.

2. The smallest room seating capacity, the average room seating capacity, and the largest room seating capacity.

3) The number of speakers attending the conference.

4. The number of presentations being given at the conference.

5. The number of presentations being given in rooms whose capacity is below 100.

6. The number of sessions taking in place in rooms that can serve refreshments.