the value of `40 c_31+sum_(r=0)^10(C_(10+r)^(40-r))` is equal to

The value of sum_(r=0)^(10)((10)/(r))((15)/(14-r)) is equal to.

the value of'"" (40)C_(31)+sum_(r=0)'""^(40+r)C_(10-r) is equal to

The value of sum_(r=0)^50 (.^(100)C_r.^(200)C_(150+r)) is equal to

The value of sum_(r=0)^(20)r(20-r)(^(20)C_(r))^(2) is equal to 400^(39)C_(20) b.400^(40)C_(19) c.400^(39)C_(19) d.400^(38)C_(20)

sum_(r=0)^(n)(""^(n)C_(r))/(r+2) is equal to :

sum_(r=0)^(n)(""^(n)C_(r))/(r+2) is equal to :

The value of sum_(r=0)^(10)(r)^(20)C_(r) is equal to 20(2^(18)+^(19)C_(10)) b.10(2^(18)+^(19)C_(10)) c.20(2^(18)+^(19)C_(11)) d.10(2^(18)+^(19)C_(11))

The value of sum_(r=0)^(n) r(n -r) (""^(n)C_(r))^(2) is equal to

The value of sum_(r=0)^(n) r(n -r) (""^(n)C_(r))^(2) is equal to

The value of sum_(r=0)^(20)r(20-r) (.^(20) C_r)^2 is equal to a. 400^(39)C_(20) b. 400^(40)C_(19) c. 400^(39)C_(19) d. 400^(38)C_(20)