A department store chain has up to 18,000 to spend on television station, where a 30-second ad cost 1,000 on daytime TV and is viewed by 14,000 potential customers, 2,000 on prime-time TV and is viewed by 24,000 potential customers, and 1,500 on late-night TV and is viewed by 18,000 potential customers. The television station will not accept a total of more than 15 ads in all there time periods