If eight persons are to address a meeting, then the number of ways in which a specified speaker is to speak before another specified speaker, is

IF eight person are to address a meeting , then the number of ways in which a specified speaker is to speak before another specified speaker is

S_1 ,S_2 ,. . . S_(10) are the speakers in a conference if S_1 addresses of ways in which a specified speaker is to speak before another specified speaker is

A,B,C are three persons amongst seven persons who speak at a function . The number of ways in which it can be done if A speaks before B and B speaks before C is

A,B ,C are three persons among 7 persons who speak at a function.The number of ways in which it can be done if A speaks before B and B speaks before C is

Six boys are to be seated in a row.The number of ways in which any 3 boys are not seated in the places specified to them,is