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Permutations and Combinations question

2019 · 10 Jan · Shift 2 · Q37
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  5. /2019 · 10 Jan · Shift 2 · Q37

Permutations and Combinations question

2019 · 10 Jan · Shift 2 · Q37

JEE MainMathematicsPermutations and CombinationsMCQ+4 / −1
If ∑r=025{50Cr.50−rC25−r}=K(50C25),  \sum\limits_{r = 0}^{25} {\left\{ {{}^{50}{C_r}.{}^{50 - r}{C_{25 - r}}} \right\} = K\left( {^{50}{C_{25}}} \right)} ,\,\,r=0∑25​{50Cr​.50−rC25−r​}=K(50C25​), then K is equal to :
  1. A
    224
  2. B
    225 −-− 1
  3. C
    225
  4. D
    (25)2
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