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Most Important Selected Qs for JEE AdvancedMathematicsBinomial Theorem

If _ r=1 ¹⁰ r(r-1) ¹⁰ C_r=k 2^9 , then k is equal to

Options

  1. A10
  2. B45
  3. C90
  4. D100

Correct answer

B. 45

Step-by-step solution

Using ^n C_r= n r n-1 r-1 = n(n-1) r(r-1) n-2 r-2 is equal to

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