A janitorial service, Mother's Helpers, provides workers to clean office buildings during late evening hours using workers with two skill levels, 1 and 2. Each level 1 person is paid $12 per hour and each level 2 person is paid $8 per hour. The workers wash floors and vacuum offices. Each level 1 person can vacuum 9 offices per hour, whereas each level 2 person can vacuum only 2 offices per hour. Each level 1 person can wash 2 floors per hour and each level 2 person can wash 3 floors per hour. In order to complete a new job in the allotted time, 18 offices must be vacuumed per hour and 12 floors must be washed per hour. Use Excel and determine the number of each type of person that will be needed to complete the job within the allotted time and at minimum cost.