Answer:
3192 persons! ✔️
Step-by-step explanation:
From the statement, we know that μ = 40 [minutes] and σ = 6 [minutes]
There are 3900 people. And we need to find how many of the lie within one standard deviation below the mean and two standard deviations above the mean.
We need to find the probability between: 34 minutes and 52 minutes. With the help of a calculator we get that the probability is: P(34<z<52) = 0.8186
Therefore, 0.8186×3900 = 3192 persons! ✔️