If there are 8 tables with couples, that would cover 16 out of 56 people, which means that 40 people total are sitting at four-person tables. Since we now know that 40 people are sitting at four-person tables, and we can obviously tell that four people sit at a four-person table, we can divid 40 by 4 to find that there are 10 four-person tables.
Final answer: 10 four-person tables.
