What is the sum of the ages of A and B?

E is sitting at the edge and 2nd to the right of C. C is 8 years old. F, who is the oldest person, is sitting three places away from E and is sitting at the corner. So, E is sitting at the edge which means we have four possible places for E. Case-1 G, who is 1 year elder than D, is sitting opposite to D. A is 2 years elder than B, and both of them are either sitting at the corner or at the edge. A and G are not immediate neighbors. Now, G is sitting opposite to D which is not possible in case I and III so, these cases are rejected. Also, in case IV, if we place G and D opposite then we can’t place A and B on the same side of the table so, case IV is also rejected. A must be 5 years old and B must be 3 years old also, D must be 9 years old which means G is 10 years old. Then final arrangement is shown below: