If `^n C_r=84 ,^n C_(r-1)=36 ,a n d^n C_(r+1)=126 ,` then find the value of `ndot`

If ^n P_r=^n P_(r+1)a n d^n C_r=^n C_(r-1,) then the value of n+r is.

If ""^(n)P_(r)=3024 & ""^(n)C_(r)=126 then the value of r =

If .^(n)C_(r-1)=36, .^(n)C_(r)=84 and .^(n)C_(r+1)=126 , find n and r.

If ""^(n)P_r = ""^(n)P_(r-1) and ""^(n)C_(r) = ""^(n)C_(r-1) , find the values of n and r.

If ""^(n)P_r = 360 , ""^(n)C_r = 15 then find the value of n =…………………….

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

If ""^(nP_(r)=""^(n)P_(r+1) and ""^(n)C_(r)=""^(n)C_(r-1) find n and r.

.^((n-1)C_(r) + ^((n-1)) C_((r-1)) is

If a_(n) = sum_(r=0)^(n) (1)/(""^(n)C_(r)) , then the value of (sumsum)_(0leiltjlen) (i/(""^(n)C_(i))+j/(""^(n)C_(j)))