An online furniture store sells chairs for $200 each and tables for $700 each. Every
day, the store can ship no more than 18 pieces of furniture and must sell at least
$7600 worth of chairs and tables. If 6 chairs were sold, determine all possible values
for the number of tables that the store must sell in order to meet the requirements.
Your answer should be a comma separated list of values. If there are no possible
solutions, submit an empty answer.