Hula Products has reintroduced the hula hoop to the world and faces a growing demand for its product in two distinct markets: the United States and Europe. Demand in these markets is: Pu = 20 - .1Qu and PE = 10 - .05QE.. where all quantities are expressed in thousands of units (i.e. Qu = 50 means 50 thousand units). Hula can produce hoops at no cost. The maximum Hula can produce is 80 thousand hoops. How many should be sent to Europe (QE)? Enter as a value (answer should be between zero and 80).