By dividing the man's total stored energy of 80,000 kcal by his energy expenditure of 100 kcal/km when running, we find that he could run 800 kilometers on his stored fat.
Step-by-step explanation:
The question involves calculating the total distance a 70-kg man can run based on the amount of energy stored as fat and the amount of energy he expends per kilometer. Knowing that the man has about 80,000 kcal of energy stored as fat and that he expends 100 kcal/km while running, we can determine the distance he can run using a simple division.
To find the total distance, divide the total energy stored by the energy expenditure per kilometer:
Total energy stored as fat = 80,000 kcal.
Energy expended per km while running = 100 kcal/km.
Total distance = Total energy stored ÷ Energy expended per km.
Plugging in the values:
Total distance = 80,000 kcal ÷ 100 kcal/km = 800 km.
Therefore, the man could run 800 kilometers on his stored fat, assuming fat is his only source of energy.