You may need to use the appropriate technology to answer this question. To help with preparations, a couple has devised a project network to describe the activities that must be completed by their wedding date. The following table lists the activity time estimates (in weeks) for each activity. Based only on the critical path, what is the estimated probability that the project will be completed within the given time frame? (Round your answers to four decimal places.) (a) Within 21 weeks? (b) Within 23 weeks? (c) Within 27 weeks