Find n, if P(10,r+1),P(11,r)::30:11.

Find r if : P(11,r) = P(12,r-1)

Find r if : "^10P_r= 2^9P_r .

Find r if : ^5P_r= "^6P_(r-1) .

Find r if "^5P_r = "^6P_(r-1) .

Find r if : ^10P_(r+1): "^11 P_(r)= 30:11 .

Find r if "^5P_r =2 "^6P_(r-1) .

If the greatest term in the expansion of (1+x)^(2n) has the greatest coefficient if and only if xepsilon(10/11, 11/10) and the fourth term in the expansion of (kx+ 1/x)^m is n/4 then find the value of mk.

Find the value of r, if (i) .^(11)P_(r)=990 (ii) .^(8)P_(5)+5*^(8)P_(4)=^(9)P_(r)

Find p if the points (p+1,1), (2p + 1,3) and (2p + 2, 2p) are collinear.