SSC CGL 2024 Tier-I · 19 September 2024, Shift 3 · General Intelligence and Reasoning · Question 14 of 99

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 triad in which the numbers are related in the same way as are the numbers of the given triads. (NOTE: Operations should be performed on the whole numbers, without breaking down the numbers into its constituent digits. E.g., 13 – Operations on 13 such as adding/deleting/multiplying etc. to 13 can be performed. Breaking down 13 into 1 and 3 and then performing mathematical operations on 1 and 3 is not allowed.) (11, 1, 10) (13, 7, 90)

(a)(1, 2, 15)
(b)(4, 5, 19)
(c)(2, 6, 28)
(d)(3, 6, 23)

Answer

Why

Correct — B. Rule: first × second − 1 = third.

11 × 1 = 11, and 11 − 1 = 10
13 × 7 = 91, and 91 − 1 = 90

One constant, −1, works on both given triads, so it is the rule and not a coincidence.

Apply it to option (b): 4 × 5 = 20, and 20 − 1 = 19, the third number printed.

Why the others are wrong

(a)
(1, 2, 15) — 1 × 2 = 2, and 2 − 1 = 1, not 15. To reach 15 the constant would have to be +13, which fits neither given triad.
(c)
(2, 6, 28) — 2 × 6 = 12, and 12 − 1 = 11, not 28. This triple needs a constant of +16, so it is running a different relation.
(d)
(3, 6, 23) — 3 × 6 = 18, and 18 − 1 = 17, not 23. The gap of +5 is the giveaway: every option needs its own constant except (b).

Concept

A triad analogy gives two worked examples and asks you to extend the relation. The relation is a single arithmetic link between the three numbers, and it has to hold for both given triads before you touch the options.

The NOTE narrows the search deliberately. You may add, subtract, multiply, divide or square, but 13 stays thirteen — you cannot break it into 1 and 3.

Product-with-a-constant, a × b + k = c, is worth trying early. Fix k on the first triad, confirm it on the second, then each option costs one multiplication and one subtraction.

Both given triads are needed. Checked alone, (11, 1, 10) also fits the far simpler 11 − 1 = 10, and that rule collapses on (13, 7, 90).

Key facts

The relation is first × second − 1 = third.
It holds on both given triads: 11 × 1 − 1 = 10 and 13 × 7 − 1 = 90.
Option (b) satisfies it exactly: 4 × 5 − 1 = 19.
The printed NOTE forbids digit operations, so 13 is treated as thirteen throughout.

Study next

Triad relations of the form a × b + k = c, with k fixed from the examplesTesting a candidate rule against every given example before checking optionsNumber analogies that carry the whole-number rider

Common traps

Fixing the rule from one triad only, when 11 − 1 = 10 also explains the first
Splitting 13 into 1 and 3 despite the NOTE
Spotting 13 × 7 = 91 and matching it to 90 without subtracting

The same triad format, with the same whole-number rider, is set at Reasoning Q.4, 19 Sep 2024, 16:00, where the relation is a² + b² = c. The wrapper is identical and only the operation changes, so the drill is to fit the operation, not to recall it.

Related PYQs

No directly related past PYQ was found.