A company is in charge of a construction project. Based on records of similar projects , the distribution of months x needed to complete the project is given by :
x 5 6 7 8 9
------------------------------------------------
p(x) 0.20 0.40 0.25 0.10 0.05
a- Given that the construction project is in progress at the end of the 6th month, what is the probability that the project will be finished at the end of the 8th month?
b- what is the expected number of month needed to finish the project ?