Nekita Corporation assembles tablets and smartphones at two different factories in the same city. During each hour at the first factory, 150 tablets and 300 smartphones can be assembled at a cost of $1000/hour. During each hour at the second factory, 100 tablets and 600 smartphones can be assembled at a cost of $1500/hour. If Nekita expects weekly orders for at least 30,000 tablets and at least 90,000 smartphones, how many hours per week should it schedule at each location to be able to fill the orders at minimum cost? What is the minimum cost?