Number Series

user January 8, 2024

(21) Look at this series: 7, 14, 28, 56, … What number should come next?

(a) 112
(b) 84
(c) 98
(d) 126

Correct Answer: (a) 112
$This series is based on doubling the previous number: 7 \times 2 = 14, 14 \times 2 = 28, 28 \times 2 = 56. So, the next term is 56 \times 2 = 112.$

(22) Examine this series: 3, 8, 15, 24, … What number should come next?

(a) 34
(b) 30
(c) 35
(d) 40

Correct Answer: (c) 35
$This series represents consecutive square numbers minus one: 3 = 2^2 - 1, 8 = 3^2 - 1, 15 = 4^2 - 1, 24 = 5^2 - 1. So, the next term is 6^2 - 1 = 35.$

(23) Consider this sequence: 12, 18, 27, 39, … What number is next?

(a) 50
(b) 48
(c) 48
(d) 51

Correct Answer: (c) 48
$This series is based on adding consecutive positive integers: 12 + 6 = 18, 18 + 9 = 27, 27 + 12 = 39. So, the next term is 39 + 15 = 48.$

(24) Investigate this pattern: 5, 8, 14, 23, … What number should come next?

(a) 32
(b) 35
(c) 40
(d) 45

Correct Answer: (b) 35
$This series is characterized by adding consecutive prime numbers to the previous term: 5 + 3 = 8, 8 + 6 = 14, 14 + 9 = 23. So, the next prime number is 23 + 12 = 35.$

(25) Look at this series: 2, 4, 9, 16, … What number should come next?