In geography, it is the former name of the Republic of Montenegro. In physics, it is the symbol for the measure of electrophoretic motility. In mathematics, it defines a function such that the nth derivative of that function is returned. For 15 points, identify this letter, the sixth of the Greek alphabet.
Mathematics: Beat the Stuffin’
Pencil and paper ready. Alice the usher can stuff five hundred programs in fifty minutes. Bobby and Clarissa are ushers who together can stuff five hundred programs in thirty-one point two five minutes. Dave, however, can only stuff four programs a minute. For 15 points, if all four ushers work together constantly at these rates, within one minute to a precision of zero point one minutes, tell how long it will take for them to stuff five hundred programs. Bounceback, if any, will be immediate. You have thirty seconds.
ANSWER: 16.7 minutes [accept 15.6 minutes to 17.7 minutes]