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AP EAMCET20228 Jul 2022Morning ShiftMathematicsPermutation and CombinationActual

If ¹⁰ P_r=604800 and ¹⁰ C_r=120 then r=

Options

  1. A14
  2. B7
  3. C8
  4. D16

Correct answer

B. 7

Step-by-step solution

We know that 10_ p _ r =10_ c _ r r ! 604800=120 . r ! r !=5040 r !=7 != r =7

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