If \[^{2n}{{C}_{2}}{{:}^{n}}{{C}_{2}}=9:2\] and \[^{n}{{C}_{r}}=10\], – McqOptions

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1.	If \[^{2n}{{C}_{2}}{{:}^{n}}{{C}_{2}}=9:2\] and \[^{n}{{C}_{r}}=10\], then \[r=\]
A.	1
B.	2
C.	4
D.	5
Answer» C. 4

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