Explain simply why 200 is the correct answer to: Once a week, it takes Kitty 5 minutes to pick up toys and straighten the living room. It takes another 20 minutes to vacuum the living room floor, seating and drapes. She spends 15 minutes cleaning the windows and 10 minutes dusting the furniture. After 4 weeks, how long has Kitty spent cleaning just the living room?. Explanation:
5 minutes for picking up toys, 20 minutes to vacuum, 15 minutes on windows and 10 minutes on furniture is 5 + 20 + 15 + 10 = 50 minutes. After 4 weeks, she has spent 4 weeks * 50 minutes / week = 200 minutes cleaning the living room.