SAT数学题排列组合题求解答
A={A,B,C,D,E,F,G}
B={0,1,2}
C={1,2,3,4,5,6,7,8,9}
The filing system in an office requires each file to have an alphanumeric code name of the form abc.A,B and C are the sets from which a,b,and c must be chosen.How many possible code names are there?