Answer: 91
Step-by-step explanation:
Given : The number of documentaries = 5
The number of comedies = 7
The number of mysteries = 4
The number of horror films =5
The total number of movies other than comedy = 14
Now, the number of possible combinations of 9 movies can he rent if he wants all 7 comedies is given by :-
[tex]^7C_7\times^{14}C_2\\\\\dfrac{7!}{7!(7-7)!}\times\dfrac{14!}{2!(14-2)!}\\\\=(1)\times\dfrac{14\times13}{2}\\\\=91[/tex]
Therefore, the number of possible combinations of 9 movies can he rent if he wants all 7 comedies is 91 .