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-   -   Why did we subtract 1 from 5? (http://mymathforum.com/elementary-math/344138-why-did-we-subtract-1-5-a.html)

Ganesh Ujwal April 27th, 2018 12:48 AM

Why did we subtract 1 from 5?
 
If 4 persons are invited for a party, find the number of ways in which they can be seated around a table along with the host.

Solution: Including the host, we have five persons. Now, 5 persons can arrange themselves around a table in (5-1)! = 4! = 24 ways.

Country Boy April 27th, 2018 04:09 AM

Because they are only counting the relative positions. Everybody shifting one or two places to the left, for example, would be counted as the same order.

Ganesh Ujwal April 27th, 2018 09:17 AM

Quote:

Originally Posted by Country Boy (Post 593365)
Be.....der.

Can you show it in diagram?

skipjack April 27th, 2018 10:31 AM

1 Attachment(s)
Attachment 9676
The arrangements above have different positions for H (the host) but would be counted as the same if the seating order is all that matters.


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