Home
Class 11
MATHS
If ""^(n+1)C(r+1): ""^(n)C(r):""^(n-1)C(...

If `""^(n+1)C_(r+1): ""^(n)C_(r):""^(n-1)C_(r-1)=11:6:3,` then nr =

A

20

B

30

C

40

D

50

Text Solution

Verified by Experts

The correct Answer is:
D
Promotional Banner

Similar Questions

Explore conceptually related problems

If ""_(n)C_(r-1) =36, ""_(n)C_(r)=84 and ""_(n)C_(r+1)=126 , then n=

If ""^(18)C_(15)+2(""^(18)C_16))+""^(17)C_(16)+1=""^(n)C_(3) , then n is equal to :

The arithmetic mean of ""^(n)C_(0), ""^(n)C_(1), ""^(n)C_(2)…., ""^(n)C_(n) is

If 1/(""^(4)C_(n))=1/(""^(5)C_(n))+1/(""^(6)C_(n)) , then find n

If .^(n)C_(r - 1) = 28, .^(n)C_(r) = 56 and .^(n)C_(r + 1) = 70 , then the value of r is equal to

If |(""^(9)C_(4),""^(9)C_(5),""^(10)C_r),(""^(10)C_(6),""^(10)C_(7),""^(11)C_(r+2)),(""^(11)C_(8),""^(11)C_(9),""^(12)C_(r+4))|=0 , then the value of r is equal to a)3 b)4 c)5 d)6

Prove that ""^(n+1)C_(r+1)=(n+1)/(r+1)"^nC_r