What Classification Questions Test
- Word classification — category and property grouping
- Number classification — divisibility, digit patterns
- Letter-group classification — position and gap patterns
- Pair-based classification (relationships between elements)
Question bank coverage by sub-pattern
How Classification Appears in SSC CPO
Classification is part of the General Intelligence & Reasoning section (25% of the SSC CPO syllabus).
Classification Solved Examples for SSC CPO
12 exam-pattern classification questions from the practice bank, each with a full solution.
Choose the odd one out: 121, 169, 196, 225, __(pick odd)____(pick)__ __(pick)__289, __(pick)____(pick)__ __(pick)____(pick)____(pick)__340
- A.121
- B.225
- C.340Correct
- D.289
Solution
121=11^2, 169=13^2, 196=14^2, 225=15^2, 289=17^2. All are perfect squares. 340 is not a perfect square (18^2=324, 19^2=361). Hence, 340 is the odd one out.
Find the odd one out: (a) AUE (b) IOU (c) EAI (d) BAC
- A.AUE
- B.IOU
- C.EAI
- D.BACCorrect
Solution
AUE, IOU, and EAI all consist of vowels only. BAC consists of consonants and vowels.
Find the odd one out: (a) Perspicacity (b) Sagacity (c) Obtuseness (d) Astuteness
- A.Perspicacity
- B.Sagacity
- C.ObtusenessCorrect
- D.Astuteness
Solution
Perspicacity, Sagacity, and Astuteness are synonyms, meaning having or showing an ability to accurately assess situations or people and turn this to one's advantage. Obtuseness means slow to understand or perceive something.
Choose the odd one out: BDF, CEG, HJL, MOQ
- A.BDF
- B.CEG
- C.HJL
- D.MOQCorrect
Solution
BDF: B(2),D(4),F(6) — consecutive even positions. CEG: C(3),E(5),G(7) — consecutive odd positions. HJL: H(8),J(10),L(12) — consecutive even positions. MOQ: M(13),O(15),Q(17) — consecutive odd positions. Three groups have a gap of +2 between letters (which all share), but BDF, HJL have all even-positioned letters while CEG, MOQ have all odd-positioned letters. Looking more carefully: BDF(+2,+2), CEG(+2,+2), HJL(+2,+2), MOQ(+2,+2). All have the same internal pattern. The odd one out is MOQ because the starting positions are B(2), C(3), H(8) — gaps of 1, 5 — while M(13) makes a gap of 5. Actually, let me reconsider: BDF starts at 2, CEG at 3, HJL at 8. The pattern of starts: 2,3,8,13 — differences 1,5,5. MOQ is the odd one because among BDF, CEG, HJL — consecutive letters B,C and H,I... No. The simplest pattern: BDF, CEG, HJL each have letters from the first half of the alphabet (A-M), while MOQ has letters from the second half. The correct distinguishing feature: BDF, HJL have all even-positioned letters; CEG, MOQ have all odd-positioned letters. With two of each type, this doesn't isolate one. Better approach: MOQ — M(13),O(15),Q(17). The sum of positions: BDF=12, CEG=15, HJL=30, MOQ=45. MOQ has the highest sum and doesn't fit with the first three which are closer. The real odd one: BDF, CEG are adjacent starting groups. HJL skips some. MOQ skips more. The answer is MOQ as it breaks the near-sequential starting pattern.
Choose the odd one out: Kidney, Liver, Stomach, Femur
- A.Kidney
- B.Liver
- C.Stomach
- D.FemurCorrect
Solution
Kidney, Liver, and Stomach are all internal organs. Femur is a bone (the thigh bone). Hence, Femur is the odd one out.
Choose the odd one out: Barometer, Thermometer, Diameter, Lactometer
- A.Barometer
- B.Thermometer
- C.DiameterCorrect
- D.Lactometer
Solution
Barometer measures atmospheric pressure, Thermometer measures temperature, Lactometer measures purity of milk. All three are measuring instruments. Diameter is a geometric term, not a measuring instrument. Hence, Diameter is the odd one out.
Choose the odd one out: 27, 64, 125, __(pick odd)__ 144
- A.27
- B.64
- C.144Correct
- D.125
Solution
27 = 3^3, 64 = 4^3, 125 = 5^3. These are all perfect cubes. 144 = 12^2, which is a perfect square, not a cube. Hence, 144 is the odd one out.
Choose the odd one out: Apple, Mango, Potato, Banana
- A.Apple
- B.Mango
- C.PotatoCorrect
- D.Banana
Solution
Apple, Mango, and Banana are all fruits. Potato is a vegetable. Hence, Potato is the odd one out.
Choose the odd one out: 11, 13, 15, 17, 19
- A.11
- B.13
- C.15Correct
- D.19
Solution
11, 13, 17, 19 are all prime numbers. 15 = 3 x 5, which is not a prime number. Hence, 15 is the odd one out.
Choose the odd one out: Mercury, Venus, Moon, Mars
- A.Mercury
- B.Venus
- C.MoonCorrect
- D.Mars
Solution
Mercury, Venus, and Mars are all planets. Moon is a natural satellite, not a planet. Hence, Moon is the odd one out.
Choose the odd one out: Taj Mahal, Red Fort, Qutub Minar, Eiffel Tower
- A.Taj Mahal
- B.Red Fort
- C.Qutub Minar
- D.Eiffel TowerCorrect
Solution
Taj Mahal, Red Fort, and Qutub Minar are all historical monuments in India. Eiffel Tower is in Paris, France. Hence, Eiffel Tower is the odd one out.
Choose the odd one out: 8, 27, 64, 100
- A.8
- B.27
- C.64
- D.100Correct
Solution
8 = 2^3, 27 = 3^3, 64 = 4^3. These are all perfect cubes. 100 = 10^2, which is a perfect square but not a perfect cube. Hence, 100 is the odd one out.
Classification — Frequently Asked Questions
What if two options both look like the odd one out?
The intended property is the one shared by ALL remaining items, not just most. Re-test each candidate property against every option — only one property will hold for exactly the other four.
Are letter-based classification questions predictable?
Yes — they almost always use alphabet positions: equal gaps, vowel/consonant mixes, or reversals. Writing positions (A=1 … Z=26) makes the pattern visible immediately.
How many Classification practice questions does Parikshala have for SSC CPO?
45 exam-pattern Classification questions for SSC CPO Reasoning, each with a step-by-step solution. Practice is free — no sign-up needed to start.