Question 243377
All of the pieces have to sum to 100% of her portfolio.  So we can set it up like the following:
{{{
(1/5) + (1/8) + (1/10) + (1/m) = 100%
}}}
,
where 1/m is the proportion in municipal stocks.
.
The first three terms can be combined using a least common denominator of 40.
.
{{{
(8 + 5 + 4)/40 + (1/m) = (17/40) + (1/m) = 1
}}}
.
By inspection, we can tell that 1/m must be 23/40 to make the equation true.
23/40 = 57.5%