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प्रश्न
If 8Cr − 7C3 = 7C2, find r.
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उत्तर
Given:
8Cr − 7C3 = 7C2
We have,\[{}^8 C_r = {}^7 C_2 + {}^7 C_3\]
\[ \Rightarrow r = 5\]
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