SSC CGL 2024 Tier-I · 23 September 2024, Shift 2 · General Intelligence and Reasoning · Question 25 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 10 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 combination of letters that when sequentially placed in the blanks of the given series will complete the series. X _ _ Y_X X _ _ X _ _

(a)Y X X Y Y X X
(b)X X Y Y A A X
(c)X X X Y X X Y
(d)Y Y X Y A X X

Answer

Why

Correct — C. Find the repeating unit first; do not test the options one at a time.

The series has 12 slots — X _ _ Y _ X X _ _ X _ _ — with blanks at positions 2, 3, 5, 8, 9, 11 and 12.

Rule: the whole series is the unit XXXY, laid down end to end.

Every printed letter already agrees with it: X at 1, Y at 4, X at 6, X at 7 and X at 10.

Dropping X, X, X, Y, X, X, Y into the seven blanks gives XXXY | XXXY | XXXY, so option (c) completes the series.

Why the others are wrong

(a)
Y X X Y Y X X — Putting Y at position 2 completes the line as X Y X Y X X X Y Y X X X, which has no repeating block at all.
(b)
X X Y Y A A X — This option brings in the letter A, which never appears in the printed series. A completion may only use letters the series already contains.
(d)
Y Y X Y A X X — A appears again, at position 9, and the Ys at positions 2 and 3 sit beside the printed Y at position 4, making a run of three Ys.

Concept

Blank-filling series are pattern questions, not code questions. The quick route is to guess how long the repeating unit is from the printed letters, then test that guess once.

Here 12 slots with a Y already at position 4 point straight at a four-letter unit. Check XXXY against every printed letter before touching the options; if it survives, the answer is whatever fills the blanks.

Substituting seven letters into twelve slots for each option in turn costs far more than testing one unit once.

Two of the four options include the letter A, which the printed series never uses. Spotting that removes half the option list before any pattern work begins.

Key facts

The completed series is X X X Y X X X Y X X X Y — the unit XXXY laid down end to end.
Printed letters sit at positions 1, 4, 6, 7 and 10, and all five agree with XXXY.
A valid completion uses only the letters already present in the series.

Study next

Blank-filling series over three or more distinct letters, where the repeating unit runs longerAlphabet-run series such as ABC_FG_JK, which repeat a skip rather than a fixed unitSeries in which the unit itself grows: XY, then XXY, then XXXY

Common traps

Testing the options one at a time instead of finding the block first
Miscounting which slots are blank when the printed string runs the letters together
Accepting an option that introduces a letter the series never uses

SSC sets this form over two or three letters, or over a run of the alphabet.

Also asked 11 Sep 2024, 09:00, Reasoning Q.10, a longer three-letter series with eight blanks to fill — q p _ r _ r q _ p _ r p _ q _ p r _ p _ q — and 26 Sep 2024, 12:30, Reasoning Q.1 (ABC_FG_JK_MOPQ_TUV_Y).

Related PYQs

No directly related past PYQ was found.