a) The arrangement of 9 paintings can be done 9 ways.
b) The arrangement of the 4 out of 9 paintings will be done as 21 ways.
<h3>What is the combination?</h3>
The arrangement of the different things or numbers in a number of ways is called the combination.
a) Here if she has 9 paintings so the number of the arrangements will be

b) The arrangement of the 4 out of 9 paintings will be

Therefore the arrangement of 9 paintings can be done 9 ways and the arrangement of the 4 out of 9 paintings will be done as 21 ways.
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