Approximately how many calories should a person who weighs 160 pounds consume per day

Until the age of 3 or 4 or 5, you can relate a person's weight to the
amount of energy he needs to take in every day.  After that, you can't.
It starts to depend on a lot of other things, besides just body weight.  

Here's a silly way to think about this:

Let's say we have two people.
 
-- One person is 30 years old, height 5-ft 8-in, weight 160 pounds.
Employed as a mail carrier, walks a 7-mile route every day.

-- The second person is 9 years old, height 4-ft 6-in, weight 160 pounds.
Enrolled in the 4th Grade.  Rides the bus to and from school.
After dinner and homework, watches TV, plays video games, or surfs the web.

Both of these people weigh 160 -pounds.
Do you think they should both get the same number of daily calories ?