Home
Class 12
MATHS
If ""^(n)C(r-1)=36,""^(n)C(r)=84 and ""^...

If `""^(n)C_(r-1)=36,""^(n)C_(r)=84` and `""^(n)C_(r+1)=126`, then r is equal to

A

1

B

2

C

3

D

4

Text Solution

Verified by Experts

The correct Answer is:
C
Promotional Banner

Topper's Solved these Questions

  • PERMUTATIONS & COMBINATIONS

    AAKASH SERIES|Exercise PRACTICE EXERCISE|163 Videos

  • PERMUTATIONS & COMBINATIONS

    AAKASH SERIES|Exercise EXERCISE-I|60 Videos

  • PARTIAL FRACTIONS

    AAKASH SERIES|Exercise PRACTICE EXERCISE|31 Videos

  • PROBABILITY

    AAKASH SERIES|Exercise Practise Exercise|165 Videos

Similar Questions

Explore conceptually related problems

IF ""^(n) C_((r-1))=36 ,""^(n)C_(r)=84 , ""^(n)C_(r+1)=126 , then r=

IF ""^(n)P_(r)=840,""^(n)C_(r)=35 then n=

""^(n) C_(r-1) = 330 ,""^(n)C_(r)=462 , ""^(n)C_(r+1) = 462 implies r=

If ""^(n)C_(r-1):""^(n)C_(r):""^(n)C_(r+1)=2:4:5 then (n,r) is

If ""^(n)C_(r) +""^(n) C_(r+1)= ""^((n+1)) C_(x) then x=

If ""^(n)P_(r)=""^(n)P_((r+1)) and ""^(n)C_(r) = ""^(n)C_(r-1), then (n,r) =

If ""^(n)C_(r)=""^(n)C_(r-1) and ""^(n)P_(r+1) = 9 .""^(n)P_(r) then (n,r)=

""^(n) C_(r+1)+2""^(n)C_(r) +""^(n)C_(r-1)=

IF ""^(n) P_(r)=720,""^(n)C_(r)=120 then (n,r) =

If ""^(n)P_(r)=5040 and ""^(n)C_(r)=210, find n and r.

AAKASH SERIES-PERMUTATIONS & COMBINATIONS-EXERCISE-II
  1. If ""^(n-1)C(3)+""^(n-1)C(4)gt""^(n)C(3), then

    Text Solution

    |

  2. If ""^(n)C(4),""^(n)C(5),""^(n)C(6) are in A.P., then the value of n i...

    Text Solution

    |

  3. If ""^(n)C(r-1)=36,""^(n)C(r)=84 and ""^(n)C(r+1)=126, then r is equal...

    Text Solution

    |

  4. The value of 2^(n)n!(1.3.5.....(2n-1)) is

    Text Solution

    |

  5. If a(n)=sum(r=0)^(n)(1)/(""^(n)C(r)) then sum(r=0)^(n)(r)/(""^(n)C(r))...

    Text Solution

    |

  6. ""^(n)C(r)+4.""^(n)C(r-1)+6.""^(n)C(r-2)+4.""^(n)C(r-3)+""^(n)C(r-4) i...

    Text Solution

    |

  7. The sum sum(i=0)^(m)((10)/(i))((20)/(m-i)) is maximum when m is

    Text Solution

    |

  8. In a football championship there were played 153 matches. Every two te...

    Text Solution

    |

  9. From a group of persons the number of ways of selecting 5 persons is e...

    Text Solution

    |

  10. In a chess tournament where the participants were to play one game wit...

    Text Solution

    |

  11. A teacher takes 3 children from her class to the zoo at a time as ofte...

    Text Solution

    |

  12. From 0 to 9, four digited numbers can be formed such that the digits a...

    Text Solution

    |

  13. The total number of 4 digit numbers in which the digits are in descend...

    Text Solution

    |

  14. There are 12 balls numbered from 1 to 12. The number of ways in which ...

    Text Solution

    |

  15. The number of ways in which we can select four numbers from 1 to 30 so...

    Text Solution

    |

  16. The number of ways in which 4 vowels and 2 consonants be chosen from E...

    Text Solution

    |

  17. The number of ways in which 5 players be chosen from 12 players so as ...

    Text Solution

    |

  18. The number of ways in which a team of eleven players can be selected f...

    Text Solution

    |

  19. Acommittee of 12 members is to formed from 9 women and 8 men ...

    Text Solution

    |

  20. A cricket 11 is to be selected out of 14 players of whom 5 are ...

    Text Solution

    |