independant variables?

I'm a little confused on the whole dependent-independent thing.... I'm doing a multiple linear regression with 13 variables in order to predict someone's overall attitude on an issue from a likert scale. One of the variables is household size and another is household wealth. However, I'd rather use a per capita household wealth variable in the regression. That is, household wealth divided by household size. But if household size is already in the regression does that mean I am not allowed to include another variable in which household size is the denominator? Or if household size is already in the regression and I use the absolute household wealth variable is household size being controlled for to the extent that household wealth can be considered per capita anyways?