Answer: 0.8490
Step-by-step explanation:
Given : The population of lengths of aluminum-coated steel sheets is normally distributed with a mean of 30.0 inches and a standard deviation of 0.9 inches.
i.e.
and 
Let x denotes the lengths of aluminum-coated steel sheets.
Required Formula : 
For n= 36 , the probability that the average length of a sheet is between 29.82 and 30.27 inches long will be :-

∴ Required probability = 0.8490
Distance = Speed × Time
Distance = (4.5 mi)/(0.75 h) × (3.5 h) = 21 mi
The walker will cover 21 miles in 3.5 hours at that pace.