Nekita Corporation assembles cell phones and smart phones at two different factories within the same city. During each hour at the first factory, 15 cell phones and 30 smart phones can be assembled at a cost of $100/hour. During each hour at the second factory, 10 cell phones and 60 smart phones can be assembled at a cost of $150/hour. If Nekita expects weekly orders for at least 15,000 cell phones and at least 45,000 smart phones, 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?