Permutations And Combinations Question 102
Question: If $ \alpha {{=}^{m}}C_2 $ , then $ ^{\alpha }C_2 $ is equal to
Options:
A) $ ^{m+1}C_4 $
B) $ ^{m-1}C_4 $
C) $ 3.{{\ }^{m+2}}C_4 $
D) $ 3\ .{{\ }^{m+1}}C_4 $
Correct Answer: D $ \therefore $ $ ^{\alpha }C_2{{=}^{m(m-1)/2}}C_2=\frac{1}{2}.\frac{m(m-1)}{2}{ \frac{m(m-1)}{2}-1 } $ $ =\frac{1}{8}m(m-1)(m-2)(m+1) $ $ =\frac{1}{8}(m+1)\ m(m-1)(m-2)=3\ .{{\ }^{m+1}}C_4 $
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Answer:
Solution:
BETA
