Quote (cialda @ 4 Dec 2013 00:04)
this ^. your above looked fine - just rewriting in case he wishes to vary the % yield as well.
S+B = 1
SC + BD = 8% portfolio yield
S & B are the fraction of the portfolio of stocks and bonds representative.
C is the yield on stocks, and D as a yield on bonds - yields should be % (9% yield or 3% return).
you cannot vary all 4 variables at once.
grrrr, don't confuse the op even more
if you want to make a general formula it would be
C=yield on item one, with A being the percentage of item one needed
D=yield on item two, with B=1-A being the percentage of item two needed
to achieve a yield Y with C<=Y<=D (assuming C<D) the formula would be
(note if C=D any mix would do)
A*C+(1-A)*D=Y
and only A would be a variable, with C,D,Y being given for the specific target