Question 417976: 1). there are 3 up escalators and one elrvator to take shoppers from first to second floor there are 3 down escalator and the same elevator to take shoppers from second floor to first floor. in how many ways can a shoppers go from first floor to the second floor and back?
2). how many 11 digits numbers are possible if the first digits are 9 and 6, the fifth one is 7 and the last two are 2 and 3?
that you for your help Answer by sudhanshu_kmr(1152) (Show Source):