Please answer question in excel format.

6. Flash Fasttrack (associate dean of janitorial services at Wombat University) must schedule the regular maintenance by his janitorial engineers. There are two crews: sweeping crew and waxing crew. Union rules prohibit sweepers from waxing and waxers from sweeping. A build ing'foors must first be swept before they can be waxed. Flash must schedule the order in which maintenance crews will visit each of Wombat US six buildings. He wished to minimize the sequence's total completion time. Times required to sweep and wax each building are as follows: Sweeping Time Waxing Time (Hours) (Hours) 18 10 Building Astronomy Biology Chemistry Drama English Foreign language 15 a. Schedule the crews through the buildings. b. When will the waxing crew start and stop work in the chemistry building? c. During the schedule, for how much time are sweepers and waxers available for other activities? 1