Number Series

(46) Examine this series: 3, 6, 12, 24, … What number should come next?

• (a) 42
• (b) 36
• (c) 30
• (d) 48

Answer

Correct Answer: (d) 48
This series is characterized by doubling the previous term: 3 \times 2 = 6, 6 \times 2 = 12, 12 \times 2 = 24. So, the next term is 24 \times 2 = 48.

(47) Investigate this pattern: 4, 7, 11, 16, … What number should come next?

• (a) 21
• (b) 22
• (c) 22
• (d) 23

Answer

Correct Answer: (c) 22
This series is characterized by adding consecutive positive integers to the previous term: 4 + 3 = 7, 7 + 4 = 11, 11 + 5 = 16. So, the next term is 16 + 6 = 22.

(48) Consider this sequence: 25, 20, 16, 13, … What number is next?

• (a) 9
• (b) 10
• (c) 11
• (d) 12

Answer

Correct Answer: (b) 10
This series represents a decreasing pattern by subtracting consecutive prime numbers from the previous term: 25 - 5 = 20, 20 - 4 = 16, 16 - 3 = 13. So, the next prime number is 2, and when subtracted from 13, it becomes 11.

(49) Investigate this pattern: 18, 20, 23, 27, … What number should come next?

• (a) 30
• (b) 32
• (c) 33
• (d) 35

Answer

Correct Answer: (b) 32
This series is characterized by adding consecutive positive integers to the previous term: 18 + 2 = 20, 20 + 3 = 23, 23 + 4 = 27. So, the next term is 27 + 5 = 32.

(50) Look at this series: 6, 11, 18, 27, … What number should come next?

• (a) 35
• (b) 38
• (c) 41
• (d) 45

Answer

Correct Answer: (b) 38
This series represents consecutive square numbers plus 2: \(2^2 + 2 = 6, 3^2 + 2 = 11, 4^2 + 2 = 18, 5^2 + 2 = 27. So, the next term is \(6^2 + 2 = 38.\)