QLR, JPD, RNU, GNC, SPX, DLB, __
If the letters from T to Z are interchanged by the letters A to G in such a way that A takes the position of T and so on, then which will be the third letter to the left of 18th letter from right? English alphabet : A B C D E F G H I J K L M N O P Q R S T U V W X Y Z
what is next in the number series 9, 54, 135, 252