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Answer:
6188
Step-by-step explanation:
Number of children's movies = 4
Number of comedy movies = 7
Number of mystery movies = 7
Number of horror movies = 5
Total number of movies to be rented = 9 out of which 4 are fixed to be children's movies
To find:
Number of different combinations to rent 9 movies out of which 4 are children's movies
Solution:
Number of movies left to be rented = 9 - 4 = 5
Number of movies left out of which these 5 are to be rented = 7 + 7 + 5 = 17
Now, there are a total of 17 movies out of which 5 are to be selected.
Therefore, we can use:
[tex]_nC_r = \dfrac{n! }{r!(n-r)!}[/tex]
where, [tex]n = 17[/tex]
[tex]r = 5[/tex]
[tex]_{17}C_5 = \dfrac{17! }{5!(12)!}\\\Rightarrow \dfrac{17.16.15.14.13}{5.4.3.2.1} = \bold{6188}[/tex]