@re2pect – here is how I did it (my way of getting the answer I have not read yet what you posed as GLEIM's explanation)
Corporation has 5,000 stock outstanding with a basis of $500k and the particular shareholder owns 200 shares of their stock at @ $100 each. With that infor you get that the basis per share of teh corp is also the $100 each. So my logic said that of the total distribution, the shareholder would receive its proportional share which is 200/5,000 = 4% ownership. Now, accumulated and current E&P total 90k, so the 125k distribution is dividend to the extent of 90k. Out of those 90k, the shareholder is entitled to 4% of it. Thus, 90k 8 4% = 3.6K
Now Reading GLEIM's explanation. They did it in a more complicated way, but I think is the same as I did at the end.
BEC - PASSED
AUD - 8/29/16
FAR - TBS
REG - TBS