SOLUTION: in how many ways can five couples be seated in a row if a. there are no restrictions? b. each couple must be seated together? c. each husband must be seated to the left of his w

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Question 1103434: in how many ways can five couples be seated in a row if
a. there are no restrictions?
b. each couple must be seated together?
c. each husband must be seated to the left of his wife?
Answer by ikleyn(52748) About Me  (Show Source):
You can put this solution on YOUR website!
.
in how many ways can five couples be seated in a row if 

a.  there are no restrictions?                             10! = 10*9*8*7*6*5*4*3*2*1 = 3628800 ways.


b.  each couple must be seated together?                   5%21%2A2%5E5 = 120*32 = 3840 ways  (120 permutations for 5 objects, each of which can be in one 
                                                          of the two states: (h,w)  or (w,h),  where "h" stands for husband and "w" stands for wife.


c.  each husband must be seated to the left of his wife?   5! = 5*4*3*2*1 = 120 ways.