DRDO Multi tasking staff Model paper 8

Given series is ZDD2, XHD3, VLF5, ?, RTH11, PXH13.

Alphabets	A	B	C	D	E	F	G	H	I	J	K	L	M
Positional value	1	2	3	4	5	6	7	8	9	10	11	12	13
Positional value	26	25	24	23	22	21	20	19	18	17	16	15	14
Alphabets	Z	Y	X	W	V	U	T	S	R	Q	P	O	N

Last elements are prime numbers arranged in increasing order.
The first letter in the series is alphabet following the sequence.
Z - 2 → X; X - 2 → V; V - 2 → T ; T - 2 → R; R - 2 → P
Second element is obtained by,
D + 4 → H; H + 4 → L; L + 4 → P; P + 4 → T; T + 4 → X
Third element:
D + 0 → D; D + 2 → F; F + 0 → F; F + 2 → H; H + 0 → H
Hence, the missing term in the series is TPF7.