If `.^(n)P_(r)=720 and .^(n)C_(r)=120` then find the value of r.

If .^(n)P_(r) =360 and .^(n)C_(r)=15 , then find the value of r.

If .^(n)P_(r) = 720 and .^(n)C_(r) = 120 , then find r. .

If .^(n)P_(r)=990 and .^(n)C_(4) 165 , then find the value of r.

If .^(n+r+1)P_(2)=72and.^(n-r)P_(2)=12 then find the values of n and r.

If ""^n C_(r-1) = 36, ""^(n) C_(r) = 84 and ""^(n) C_(r+1) = 126 then find the value of r.

If ^(n)P_r = 840 and ^(n)C_r = 35 then find the value of r.

If .^(n)P_(r) = 720 and .^(n)C_(r) = 120 , then find r. = (5 xx 4 xx 3)/(3 xx 2 xx1) xx (4xx 3 xx 2)/(3 xx 2xx1) = 10 xx 4 = 40 .

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

If ""^(n)P_(r)=840 and ""^(n)C_(r)=35 , then the value of r is equal to