As part of an experimental study a volunteer agrees to

have 10g mannitol injected intravenously. After sufficient time for

equilibration, blood is drawn and the concentration of mannitol in the plasma

is found to be 65 mg / 100 ml. Urinalysis reveals 10% of the mannitol had been

excreted into the urine during this time period.

What is the approximate (to the nearest litre (L))

extracellular fluid volume of this volunteer?