A 32-yrs-old man visits you for a periodic health examination. He has no complaints at this time. He is 170 cm (5 ft 7 in) tall and weights 75 kg. In this patient, the volumes of total body water, intracellular fluid, and extracellular fluid are, respectively.
40L, 30L, 10L
45L, 30L, 15L
45L, 35L, 10L
50L, 25L, 25L
Total body water (TBW) in liters equals approximately 60% of body weight in kilograms and therefore equals 45 L in a 75-kg person. Intracellular volume = 2/3 of TBW and is therefore 30 L in this case. Extracellular volume = 1/3 of TBW and is therefore 15 L in this case.