Answer:
31.5 days
Step-by-step explanation:
We.solve using z score formula
z-score is is z = (x-μ)/σ,
where x is the raw score
μ is the population mean
σ is the population standard deviation.
The 5th percentile z score = -1.645
Mean = 66
Standard deviation = 21
Hence:
-1.645 = x - 66/21
-1.645 × 21 = x - 66
-34.545 = x - 66
-34.545 + 66 = x
x = 31.455 days
Approximately to the nearest round integer
= 31.5 days
Therefore, driver use a commuter rail line 31.5 days annually to be in the top 5% of rail users
