Answer: the due date would be 92 weeks
Step-by-step explanation:
Since the time required to complete a project is normally distributed, we would apply the formula for normal distribution which is expressed as
z = (x - µ)/σ
Where
x = number of weeks.
µ = mean
σ = standard deviation
From the information given,
µ = 80 weeks
σ = 10 weeks
If a construction company bidding on this contract wishes to be 90 percent sure of finishing by the due date, the z score corresponding to 90%(90/100 = 0.9) is 1.29
Therefore,
1.29 = (x - 80)/10
x - 80 = 1.2 × 10
x - 80 = 12
x = 80 + 12 = 92