Odd man out and series

(76) Which number does not belong in the series: 10, 13, 16, 21, 26, 31, 37?

• (a) 16
• (b) 21
• (c) 26
• (d) 37

Answer

Correct Answer: (d) 37
The pattern is adding consecutive prime numbers: 3, 3, 5, 5, 5, 6, …
The number 37 does not fit this pattern.

(77) Look at this series: 12, 10, 8, 6, 4, … What number should fill the blank?

• (a) 2
• (b) 0
• (c) 3
• (d) 2

Answer

Correct Answer: (d) 2
This is a series where each number is decreasing by 2: 12, 10, 8, 6, 4, 2, …
The next number should be 2.

(78) Which number does not belong in the series: 14, 28, 42, 56, 72, 90, 112?

• (a) 42
• (b) 56
• (c) 72
• (d) 112

Answer

Correct Answer: (d) 112
The pattern is adding 14 to each number: 14, 28, 42, 56, 70, 84, 98, …
The number 112 does not fit this pattern.

(79) Look at this series: 3, 7, 15, 31, 63, … What number should fill the blank?

• (a) 127
• (b) 64
• (c) 32
• (d) 127

Answer

Correct Answer: (d) 127
This is a series where each number is doubled and then increased by 1: 3, 3×2+1, 7×2+1, 15×2+1, 31×2+1, …
The next number should be \(63×2+1 = 127\).

(80) Which number does not belong in the series: 8, 16, 32, 64, 128, 256, 512?

• (a) 32
• (b) 64
• (c) 128
• (d) 512

Answer

Correct Answer: (d) 512
The pattern is doubling each number: 8, 16, 32, 64, 128, 256, 512, …
The number 512 does not fit this pattern.