1 Intracellular fluid (2/3 of body water). 2  Per Guyton, in a body containing 40 litres of fluid, about 25 litres is intracellular, which amounts to 62.5% (5/8), close enough to the 2/3 rule of thumb. 3  Jackson's texts states 70% of body fluid is intracellular. 4  Extracellular fluid (1/3 of body water).
However, if you provided support to your brother, depending on the level of support and your brotherâs gross income for 2010, you may be able to claim him as a dependent on your tax return (under the qualifying relative rules).
Suppose you live alone and your only income is SSI. Your brother pays your rent of $800. We count this payment as in-kind support and maintenance. Although the rent is $800, we limit how much of the $800 we count by using a presumed maximum value (PMV) rule. The PMV is equal to 1/3 of the Federal benefit rate plus $20.