Q: 82 (IAS/2005)

There are 6 persons-A, B, C, D, E and F. They are to be seated in a row such that B never sits any where ahead of A and C never sits any where ahead of B. In how many different ways can this be done?
question_subject: 
Maths
question_year: 
2005
question_exam: 
IAS
question_sub_subject: 
Mathematics
question_topic: 
Mathematics
stats: 
0,56,40,0,32,56,8