Mark has lots of tables in his (large) house. Each circular table will seat $5$ people and each rectangular table will seat $8$ people.
At his birthday party there will be $36$ people, including himself.
Mark wants there to be no empty seats at any of the tables that are used.
How many tables of each type does Mark need to use in order to achieve this?
Is this the only possibility?
If you liked this problem, here is an NRICH task
which challenges you to use similar mathematical ideas.