Permutations And Combinations Question 106
Question: If $ ^{10}C _{r}{{=}^{10}}{C _{r+2}} $ , then $ ^{5}C _{r} $ equals [RPET 1996]
Options:
A) 120
B) 10
C) 360
D) 5
Correct Answer: D $ ^{10}C _{r} = ^{10}C _{r+2}\Rightarrow r + (r+2) = 10\Rightarrow r=4 $ $ \therefore $ $ ^{5}C _{r}{{=}^{5}}C_3=\frac{5\ !}{2\ !\ 3\ !}=10 $
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Answer:
Solution:
BETA
