Question

room attendants at your hotel typically clean one room every 20 minutes. one-fifth of the rooms take 40% longer to clean due to various issues. how much time will it take to clean 175 rooms?

Answer 1

Method 1 - treat all rooms the same and add the extra time for difficult rooms
Time = 175 x 20 + 175/5 x 20 x 0.4 = 3500 + 280 = 3780 min = 63 hours

Method 2 - calculate standard rooms and difficult rooms separately
Time = 175 x 4/5 x 20 + 175/5 x 20 x 1.4 = 2800 + 980 = 3780 min = 63 hours