I was reading a guide on long distance hiking. The book, paperback, mentioned that long distance hikers need to eat 2 pounds of food per day.
Then it went on to say that a hiker couldn’t take 10 days of food because that would mean a 40 pound pack would weigh 60 pounds.
First, you have to eat.
Second, it only weighs that when you get out of your car/transport. It drops 2 pounds per day.
So on the 10th day it weighs 40 pounds, not 60 pounds.
The book may have meant to imply it weighs 60 pounds on the first day, but to me the wording reads that the pack weighs 60 pounds all 10 days.