Number Series Completion - Study Mode

[#141] Find out the wrong term: 2, 5, 10, 17, 26, 37, 50, 64
Correct Answer

(D) 64

Explanation

Solution: The term of the series are (1 2 + 1)(2 2 + 1)(3 2 + 1)(4 2 + 1)(5 2 + 1)(6 2 + 1)(7 2 + 1),.............. So, 64 is wrong and must be replaced by (8 2 + 1) i.e., 65

[#142] Find out the wrong term: 3, 7, 15, 39, 63, 127, 255, 511
Correct Answer

(B) 39

Explanation

Solution: The correct pattern is × 2 + 1. So, 39 is wrong and must be replaced by (15 × 2 + 1) i.e., 31.

[#143] 20, 20, 17, 17, 14, 14, 11, ... choose which pair of numbers comes next?
Correct Answer

8, 8

Explanation

Solution: This is a simple subtraction with repetition series. It begins with 20, which is repeated, then 3 is subtracted, resulting in 17, which is repeated, and so on.

[#144] 61, 57, 50, 61, 43, 36, 61, ... choose which pair of numbers comes next?
Correct Answer

29, 61

Explanation

Solution: This is an alternating repetition series, in which a random number, 61, is interpolated as every third number into an otherwise simple subtraction series. Starting with the second number, 57, each number (except 61) is 7 less than the previous number.

[#145] 9, 12, 11, 14, 13, 16, 15, ... choose which pair of numbers comes next?
Correct Answer

14, 13

Explanation

Solution: This is a simple alternating addition and subtraction series. First, 3 is added, then 1 is subtracted, then 3 is added, 1 subtracted, and so on.