me understand how to solve these problems. Thank you Mary and Tom gather and sterilize various items in the hospital. It takes Mary 2 hours for this activity and it takes Tom 3 hours. When working together, How long will it take them? John is a CPA and can research and evaluate a client's financial activity in 5 hours. If he works with Ellen, they can evaluate the activity in 2 hours. If Ellen worked separately, How long would the project take? A saline solution pump can fill a vessel in 5 hours. Another pump can empty the tank in 6 hours. If both pumps are operating simultaneously, how many hours are required to fill the vessel