SSC CGL 2024 Tier-I · 25 September 2024, Shift 1 · General Intelligence and Reasoning · Question 16 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 option that represents the letters that when sequentially placed from left to right in the blanks below will complete the letter series. Z _ A _ Z _ _ Z A _ Z _

(a)ZZAZZA
(b)AZAZAZ
(c)ZZZAAA
(d)AZZAZZ

Answer

Why

Correct — A. Number the twelve slots. You are given slot 1 = Z, slot 3 = A, slot 5 = Z, slot 8 = Z, slot 9 = A and slot 11 = Z.

Rule: the three-letter group ZZA repeats across all twelve slots, so A falls on every slot whose number is a multiple of 3 and Z fills the rest.

That agrees with all six given letters: 3 and 9 carry A, while 1, 5, 8 and 11 carry Z.

The blanks sit at slots 2, 4, 6, 7, 10 and 12. Read in that order they are Z, Z, A, Z, Z, A — option (a) — and the finished line is ZZAZZAZZAZZA.

Why the others are wrong

(b)
AZAZAZ — This puts A in slot 2, right beside the given A in slot 3, producing AA. No three-letter group repeated across twelve slots can place two A's together here.
(c)
ZZZAAA — Slots 4, 5 and 6 come out as ZZZ and slots 9 and 10 as AA. The opening ZZA already fixes the repeating group, and this fill abandons it after a single repeat.
(d)
AZZAZZ — It sets A in slot 7 while slot 9 is a given A, so A would sit at slots 2, 3, 7 and 9 — spacings no fixed three-letter group can produce.

Concept

A blank-filling letter series is nearly always one short group of letters repeated, so find the group instead of testing options one by one.

Count the slots first — twelve here — and number them. Then read the letters you were handed: A at slots 3 and 9, Z at slots 1, 5, 8 and 11.

A two-letter group fails immediately, because slots 1 and 3 are both odd yet hold different letters. A three-letter group ending in A fits every given letter, and ZZA written out across twelve slots completes the line.

Reading the blanks off in strict left-to-right order is the last step, and the one candidates rush.

Each option is six letters long because there are six blanks. Count the blanks before you look at the options — a fill with the right letters in the wrong slots looks identical at a glance.

Key facts

The completed series is ZZAZZAZZAZZA, which is the group ZZA repeated to fill twelve slots.
The six blanks sit at slots 2, 4, 6, 7, 10 and 12 of twelve.
Every slot whose number is a multiple of 3 carries A, and every other slot carries Z.

Study next

Repeating-group letter series, and finding the group length from the given lettersUsing the gap between two identical given letters to bound the periodNumbering the slots as a habit before reading any option

Common traps

Filling the blanks in the order they catch the eye rather than strictly left to right
Testing each option letter by letter instead of finding the repeating group first
Miscounting the slots where two blanks stand together, as at slots 6 and 7

The same design runs at 13 Sep 2024, 09:00, Reasoning Q.14, where _ X _ F _ _ _ X T _ X _ resolves to FXT repeated, and at 17 Sep 2024, 16:00, Reasoning Q.19, where _ P _ J _ P _ P _ _ P _ resolves to JPP repeated.

Related PYQs

No directly related past PYQ was found.