How many weeks would it take an average person jogging 10 minutes per mile for 8 hours a day to jog 3987 miles?

A person who jogged for 8 hours a day can hardly be described as average!

Still, 10 minutes per mile = 60 minutes per 6 miles or 6 miles per hour.

Then 8 hours a day gives 8*6 = 48 miles per day or 48*7 = 336 miles per week.

So 3987 miles would take 3987/336 = 11.87 or nearly 12 weeks.