If^(20)C_(r)=^(20)C_(r+6)," find "r

If ^(20)C_(r)=^(20)C_(r+4), then ^(r)C_(3) is equal to a.54 b.56c.58d .none of these

If ^(20)C_(r+1)=^(20)C_(r-1), then r is equal to a.10 b.11 c.19d.12

If .^(20)C_(r)=.^(20)C_(r-10) then find the value of .^(17)C_(r) .

If ""^(20)C_(r)=""^(20)C_(r-10) , then ""^(18)C_(r) is equal to

""^(20)C_(r) =""^(20)C_(r-10), then find the value of ""^(18)C_(r)

If .^(20)C_(r+1)=.^(20)C_(r-1) then find the value of .^(10)C_(r) .

If \ ^(20)C_r=\ ^(20)C_(r+4),\ t h e n\ \ ^r C_3 is equal to a. 54 b. 56 c. 58 d. none of these

If \ ^(20)C_(r+1)=\ \ ^(20)C_(r-1),\ t h e n\ r is equal to a. 10 b. 11 c. 19 d. 12

(i) If ""^(5)P_(r)=2xx""^(6)P_(r-1) , find r. (ii) If ""^(20)P_(r)=13xx""^(20)P_(r-1) , find r. (iii) If ""^(11)P_(r)=""^(12)P_(r-1) , find r.