(a) There are 7 item in the Joanna's list.
7 distinguishable items can be arranged by 7! = 7*6*5*4*3*2*1 = 5040 ways.
(b) If "scores" are fixed as the first item in the list, it reduces the number of possible arrangements
of all other items from 7! to 6! = 6*5*4*3*2*1 = 720.
Therefore, the fraction of rankings with "scores" at the first position to the total number of arrangements is
= .