Yes, they are independent event such that occurring the first event “choosing a sophomore” does not affect the probability of occurring the second event <span>“choosing someone who replied ‘Yes’”</span><span />
Answer (13 of the original arrangements are duplicates now, as
AAAF F F FDDDDCC, AAF F F FDDDDCCA, ..., CAAAF F F FDDDDC
are identical): 900900/13 = 69300.
