Excited by the recent warm weather Jill and Kelly are doing spring cleaning at their apartment. Jill takes an exponentially distributed amount of time with mean 20 min- utes to clean the kitchen. Kelly takes an exponentially distributed amount of time with mean 30 minutes to clean the bathroom. The first one to complete their task will go outside and start raking leaves, a task that takes an exponentially distributed amount of time with a mean of one hour. When the second person is done inside, she will help the other, and raking will be done at rate 2 per hour. (Of course the other person may already be done raking in which case the chores are done.) What is the expected time until the chores are all done