SSC CGL 2024 Tier-I · 10 September 2024, Shift 2 · General Intelligence and Reasoning · Question 9 of 100

Text as printed on a candidate's response sheet for this shift; answer per SSC's tentative key as marked on that sheet. Solution last reviewed 6 September 2026.

Where this paper and its answers come from

SSC does not publish CGL question papers or a public answer key. The questions and options here are reproduced as printed on a candidate's own response sheet for this shift — the Commission's text, unchanged. Each answer is SSC's tentative key as marked on that sheet; SSC allowed challenges to it and never publishes a final key. The solutions are written by UnlockIAS.

Select the option that represents the letters that when placed from left to right in the blanks below will complete the given letter series. D F _ I J O D _ H I J O _ F H I J O D F _ I J O D _

(a)FHDHF
(b)HFHDF
(c)HFDHF
(d)HFFDH

Answer

Why

Correct — C. Find the repeating group first, then read each blank off its position inside that group.

The run I J O comes round every six slots. Writing the series in sixes:

D F _ I J O
D _ H I J O
_ F H I J O

D F _ I J O
D _

Rule: the six-letter group D F H I J O repeats unchanged.

Blank 1 is its third letter: H
Blank 2 is its second letter: F
Blank 3 is its first letter: D

Blank 4 is its third letter: H
Blank 5 is its second letter: F

Left to right that reads HFDHF, option (c).

Why the others are wrong

(a)
FHDHF — The first two blanks are swapped. The block runs D F H, so blank one takes H and blank two takes F, not the other way round.
(b)
HFHDF — Blank three opens a fresh block and must be D. This option puts H there and pushes D into blank four, which the block fills with H.
(d)
HFFDH — The first two blanks are right and the third is not. Blank three starts a block, so it takes D, while this option repeats F.

Concept

A missing-letter series is really one short group printed over and over. Find the group and the blanks fill themselves.

Look for the longest unbroken run and count the gap to its next appearance. Here I J O reappears six slots later, so the group is six letters long.

Then stack the series in rows of that length. Each blank now sits in a column with letters that are already given, and you read it straight off.

There are 26 slots in this series, which is four complete groups of six plus the first two letters of a fifth. That is why the last blank is the second letter of the group rather than the sixth.

Key facts

The repeating unit is the six letters D F H I J O.
The run I J O appears four times in this series, which is the fastest way to fix the group length at six.
26 slots is four full groups of six plus two more letters.

Study next

Repeated-block letter series and finding the periodSeries where the block shifts by one letter each cycleMixed series that alternate letters with numbers

Common traps

Guessing the block length from the first blank instead of counting to the next repeat.
Filling the blanks in the order an option prints them without checking each against its column.
Reading the series in a single line, which hides that blank three opens a block.

Sequence work runs through this shift's Reasoning section — a letter-cluster series at Q.1 and a number series at Q.15 (10 Sep 2024, 12:30). Both are solved by fixing the period before filling anything in.

Related PYQs

No directly related past PYQ was found.