Answer:
[tex]\huge\boxed{Distance:16mi}\\\huge\boxed{Displacement: 0mi}[/tex]
Step-by-step explanation:
Because Jacob starts and ends at his house, his total displacement is 0mi, because the distance from his house to his house is 0 mi.
Because Jacob travels 5 miles to the shops, then (N.B. I'm inferring here) in a straight line, 3 more miles to the post office, a total distance of 8 miles, then another 8 backwards, he travels a total distance of 16mi.
Hope it helps :) and let me know if you want me to elaborate.