Odd man out and series

(56) Which number does not belong in the series: 13, 18, 23, 33, 43, 48, 58?

• (a) 23
• (b) 33
• (c) 43
• (d) 58

Answer

Correct Answer: (d) 58
The pattern is adding 5 to each number: 13, 18, 23, 28, 33, 38, 43, …
The number 58 does not fit this pattern.

(57) Look at this series: 2, 6, 12, 20, 30, … What number should fill the blank?

• (a) 36
• (b) 40
• (c) 46
• (d) 42

Answer

Correct Answer: (d) 42
This is an arithmetic series with a common difference of 4: 2, 6, 10, 14, 18, 22, …
The next number should be \(30 + 4 = 34\), not 36.

(58) Which number does not belong in the series: 5, 15, 30, 50, 75, 105, 140?

• (a) 15
• (b) 30
• (c) 50
• (d) 75

Answer

Correct Answer: (d) 75
The pattern is adding consecutive triangular numbers: 1, 3, 6, 10, 15, 21, 28, …
The number 75 does not fit this pattern.

(59) Look at this series: 4, 9, 16, 25, 36, … What number should fill the blank?

• (a) 42
• (b) 49
• (c) 56
• (d) 49

Answer

Correct Answer: (d) 49
This is a series of perfect squares: 2^2, 3^2, 4^2, 5^2, 6^2, 7^2, …
The next number should be \(7^2 = 49\).

(60) Which number does not belong in the series: 12, 28, 48, 72, 100, 132, 168?

• (a) 48
• (b) 72
• (c) 100
• (d) 168

Answer

Correct Answer: (d) 168
The pattern is adding consecutive triangular numbers: 1, 3, 6, 10, 15, 21, 28, …
The number 168 does not fit this pattern.