need help getting eatimated time for critical path, activity variance and the probability of compleating the project in 40 weeks thanks !

Ross Hopkins, president of Hopkins Hospitality, has developed the tasks, durations, and predecessor relationships in the following table for building new motels. a) The expected (estimated) time for activity C is weeks. (Round your response to two decimal places.) b) The variance for activity C is weeks. (Round your response to two decimal places.) c) Based on the calculation of the estimated times, the critical path is d) The estimated time for the critical path is weeks. (Round your response to two decimal places)