If \[^{n}{{P}_{r}}\]= 720.\[^{n}{{C}_{r}},\] then r is equal to [Kerala (Engg.) 2001]

If \[^{n}{{P}_{r}}\]= 720.\[^{n}{{C}_{r}},\] then r is equal to [Keral

1.	If \[^{n}{{P}_{r}}\]= 720.\[^{n}{{C}_{r}},\] then r is equal to [Kerala (Engg.) 2001]
A.	6
B.	5
C.	4
D.	7
Answer» B. 5

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If \[^{n}{{P}_{r}}\]= 720.\[^{n}{{C}_{r}},\] then r is equal to [Kerala (Engg.) 2001]

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