A computer store sells two types of computers, desktops and laptops. The supplier demands that at least 150 computers be sold a month. In order to keep profits up, the number of desktops sold must be at least twice the number of laptops. The store spends $75 a week to market each desktop and $50 a week to market each laptop. How many of each type of computer must be sold to minimize weekly marketing costs? Laptops: Desktops: What is the minimum weekly marketing cost? $