Thanksgiving Time

A large Thanksgiving banquet served between 500 and 600 people. The dinner rolls came in baker's dozens (packages of 13). After everyone had been served a roll there were a number of empty packages plus one open package with 10 rolls left. The pies for dessert had each been cut into ninths, and after everyone had been served a slice there were a number of empty pie tins plus one pie tin with 4 slices left. The tables in the banquet hall each had room for 15 guests. All but one of the tables were full. How many people were seated at that last table?

Be sure to completely explain your method and your answer.  Each step you used should  be explain.  Anyone who does not understand math should be able to follow your process and get the same answer.

Have fun and good luck,
Ms. L.