An online furniture store sells chairs for $200 each and tables for $600 each. Every day, the store can ship a maximum of 32 pieces of furniture and must sell no less than
$12000 worth of chairs and tables. If 13 chairs were sold, determine the minimum
number of tables that the the store must sell in order to meet the requirements. If
there are no possible solutions, submit an empty answer.
What is the system of inequalities

Each person in an it department of 25 people works on at least one of 3 major projects: system security, program implementation, platform development. 10 people work on system security, 13 work on program implementation, and 12 work on platform development. 4 people work on system security and platform development, 5 people work on program implementation and platform development, and 2 people work on all three projects. how many people work on system security and program implementation?