# Combination rule

## Homework Statement

An accounting professional association is considering six hotels as possible sites for their next two meetings in 2001 and 2002. In how many ways can the association select the hotels...
a) if the two meetings may be held at the same hotel?
b)if the two meetings may not be held at the same hotel?

## The Attempt at a Solution

I found the answers by drawing out a tree... But i was wondering if there was a mathematical way using the counting rules i.e permutation/combinations rules etc. I was trying for a while but couldn't find one

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## Homework Statement

An accounting professional association is considering six hotels as possible sites for their next two meetings in 2001 and 2002. In how many ways can the association select the hotels...
a) if the two meetings may be held at the same hotel?
b)if the two meetings may not be held at the same hotel?

## The Attempt at a Solution

I found the answers by drawing out a tree... But i was wondering if there was a mathematical way using the counting rules i.e permutation/combinations rules etc. I was trying for a while but couldn't find one

For part a), there are six hotels and only two meetings to consider. So you only have to concern yourself with re-arranging the possibilities of the six hotels.

##{n \choose k}##

Does this look familiar to you? How about part b)?

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