If P( 5 , r ) = 5 , find the value of r

If ^(10)P_(r)=5040, find the value of r

If .^(6)P_(r): .^(6)P_(5) = 1:2 , find the value of r.

When n = 5 and r = 2, find the values of : (i) (n!)/(r!) (ii) (n!)/(r!(n-r)!)

(i) If ""^(15)P_(r)=2730, find the value of r. (ii) If ""^(10)P_(r)=5040, find the value of r.

If P(n,r)=990 and C(n,r)=165 then find the value of r

If p=4 , q=-3, r=2 find the value of 4p^2+5q-12r

If .^(15)C_(r): .^(15)C_(R-1) = 11:5 , then find the value of 'r'.

If the origin is the centroid of the triangle whose vertices are A (2,p,-3), B(q,-2,5) and C(-5,1,r), then find the values of p,q and r.