Sarah. Hannah and Mark all work together in the same ofce. They are cu neatly working. albeit independently. on the same project. If only Sarah and Hannah work on the task in the project then it would take 2 hours. If Sarah and Mark work on it, it would take 3 hours and if Hannah and Mark work on it then it would take 4 hours. (at How long would the task take ifBarah. Hannah and Mark all week on it [3] together? {bi It actually turns out that the individual effort of each of Sarah. Hannah [6] and Mark is actually given by a uniform distribution whose expected values are the values from [a] and whose upper and lower bounds of the distribution are :tlii: of the expected value. What is the mean of the variance of the work distributions of Sarah. Hannah and Mark