THREE TWO Please show ALL your work and EXPLAIN your answer. Help with the incomplete questions

Using PERT, Adam Munson was able to determine that the expected project completion time for the construction of a pleasure yacht is 24 months, and the project variance is 4. a) The probability that the project will be completed in 20 months = 0.0228 (round your response to four decimal places). b) The probability that the project will be completed in 23 months = decimal places). (round your response to four