you sometimes encounter like "How many pigeons are there is Manhattan" is that they are a very good way to judge someone's unstructured problem solving ability.
You should re-read that. I'm sure you didn't mean "there is Manhattan".
I'd fail the interview:
a) I'll annoy you with grammar corrections
b) point out that Passenger Pigeons have been extinct for quite some time.
c) African or European?
d) ask if we could change the question to something more warm and fuzzy, like estimating the number of squirrels in Los Angeles
I studied the published graphs of supernovae Ia brightness versus redshift. So I came to accept that the comparison curve on what is expected in an empty universe is correct. This certainly makes interpretation on the deviations easier. (In Wikipedia the dimming due to redshift is stated incorrectly, so my doubts were not unfounded.) See http://www.pha.jhu.edu/~bfalck/SeminarPres.html#adeptsim
"Life is a garment we continuously alter, but which never seems to fit." -- David McCord