← General Intelligence and Reasoning

Number Classification — Questions with Solutions

6 solved Number Classification questions from General Intelligence and Reasoning, as asked in SSC CGL and other SSC exams. Read the answer and explanation below, then practise the full set in the practice section.

Practise this topic

Q1. Identify the odd one: 3, 5, 7, 11, 13, 17, 19, 21

बेजोड़ (Odd one) की पहचान करें: 3, 5, 7, 11, 13, 17, 19, 21

  1. A. 21
  2. B. 13
  3. C. 11
  4. D. 19

Solution

All numbers in the series are prime numbers except 21, which is composite (divisible by 3 and 7).

Q2. Find the odd one out. $729, 1331, 2197, 3125$

बेजोड़ (Odd one) ज्ञात कीजिए। $729, 1331, 2197, 3125$

  1. A. 729
  2. B. 1331
  3. C. 2197
  4. D. 3125

Solution

$729 = 9^3$, $1331 = 11^3$, $2197 = 13^3$. $3125$ is $5^5$, not a perfect cube, making it the odd one.

Q3. Which group does not match the pattern?

कौन सा समूह पैटर्न से मेल नहीं खाता है?

  1. A. 6, 18, 54
  2. B. 4, 12, 36
  3. C. 5, 15, 40
  4. D. 7, 21, 63

Solution

The pattern is $x$, $x \times 3$, $x \times 9$. $6 \times 3=18, 18 \times 3=54$. But $5 \times 3=15$, and $15 \times 3$ should be $45$, not $40$.

Q4. Find the odd one out.

बेजोड़ (odd one out) ज्ञात कीजिए।

  1. A. 2:4:16
  2. B. 3:6:36
  3. C. 4:8:64
  4. D. 5:10:120

Solution

Pattern: $x : (x \times 2) : (x \times 2)^2$. $2:4:16$ ($4^2=16$). $3:6:36$ ($6^2=36$). $4:8:64$ ($8^2=64$). For 5:10, it should be $10^2=100$, but 120 is given.

Q5. Which group does not match the pattern?

कौन सा समूह पैटर्न से मेल नहीं खाता है?

  1. A. 6, 18, 54
  2. B. 4, 12, 36
  3. C. 5, 15, 40
  4. D. 7, 21, 63

Solution

The pattern is $x$, $x \times 3$, $x \times 9$. $6 \times 3=18, 18 \times 3=54$. But $5 \times 3=15$, and $15 \times 3$ should be $45$, not $40$.

Q6. Find the odd one out.

बेजोड़ (odd one out) ज्ञात कीजिए।

  1. A. 2:4:16
  2. B. 3:6:36
  3. C. 4:8:64
  4. D. 5:10:120

Solution

Pattern: $x : (x \times 2) : (x \times 2)^2$. $2:4:16$ ($4^2=16$). $3:6:36$ ($6^2=36$). $4:8:64$ ($8^2=64$). For 5:10, it should be $10^2=100$, but 120 is given.