Promotions are always done in the descending order.

• 10^th students must be given TC.

           (10^th class becomes vacant)

• Then 9^th students can be promoted to 10^th.

            (9^th class becomes vacant)

• 8^th students can be promoted to 9^th.

            (8^th class becomes vacant)

• 7^th students can be promoted to 8^th and so on.