Odd man out and series

(86) Which number does not belong in the series: 3, 8, 15, 24, 35, 48, 63?

• (a) 15
• (b) 24
• (c) 35
• (d) 48

Answer

Correct Answer: (d) 48
The pattern is adding consecutive square numbers: 1, 4, 9, 16, 25, 36, …
The number 48 does not fit this pattern.

(87) Look at this series: 2, 5, 10, 17, 26, … What number should fill the blank?

• (a) 37
• (b) 40
• (c) 29
• (d) 37

Answer

Correct Answer: (d) 37
This is a series where each number increases by consecutive odd numbers: 2, 2+3, 5+5, 10+7, 17+9, …
The next number should be \(26+11 = 37\).

(88) Which number does not belong in the series: 7, 16, 37, 82, 175, 364, 751?

• (a) 37
• (b) 82
• (c) 175
• (d) 751

Answer

Correct Answer: (d) 751
The pattern is squaring each number and then adding 3: 7, 7^2+3, 16^2+3, 37^2+3, 82^2+3, …
The number 751 does not fit this pattern.

(89) Look at this series: 3, 9, 27, 81, 243, … What number should fill the blank?

• (a) 729
• (b) 486
• (c) 324
• (d) 729

Answer

Correct Answer: (d) 729
This is a series where each number is multiplied by 3: 3, 3×3, 3x3x3, 3x3x3x3, 3x3x3x3x3, …
The next number should be \(243×3 = 729\).

(90) Which number does not belong in the series: 11, 23, 39, 59, 83, 111, 143?

• (a) 39
• (b) 59
• (c) 83
• (d) 111

Answer

Correct Answer: (d) 111
The pattern is adding consecutive prime numbers: 11, 23, 39, 59, 83, 111, …
The number 111 does not fit this pattern.