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Practice Questions on Series

Directions for Q33-35. One of the numbers is wrong in the following series. Identify the wrong number in the following series:
Q33) 5, 8, 3, 11, -5, 27

1) 8
2) 11
3) -5
4) 27

Solution:
Difference between the numbers is 2,-4,8,-16,32. Wrong number is 8.
Hence, option 1.

Q34) 2, 6, 12, 21, 30, 42

1) 2
2) 12
3) 21
4) 42

Solution:
Logic is 22 - 2 = 2, 32 - 3 = 6, 42 - 4 = 12, 52 - 5 = 20, 62 - 6 = 30, 72 - 7 = 42
Wrong number is 21.
Hence, option 3.

Q35) 5, 26, 122, 340, 1328, 2194

1) 122
2) 26
3) 340
4) 1328

Solution:
Logic is 23 - 3 = 5, 33 - 3 = 24, 53 - 3 = 122, 73 - 3 = 340, 113 - 3 = 1328, 133 - 3 = 2194
Wrong number is 26.
Hence, option 2.

Directions for Q36-37. In the following series one wrong number is given, find out the wrong number and identify the number that should replace the wrong number.
Q36) 68, 36, 20, 12, 7.5, 6, 5

1) 7.5
2) 8
3) 15
4) 7

Solution:
Logic is 68 - 32 = 36, 36 - 16 = 20, 20 - 8 = 12, 12 - 4 = 8, 8 - 2 = 6, 6 - 1 = 5
Wrong number is 7.5 and it should be replaced with 8.
Hence, option 2.

Q37) 2, 1, 13, 19, 99, 211

1) 11
2) 99
3) 97
4) 13

Solution:
Logic is 2×3 - 5 = 1, 1×3 + 10 = 13, 13×3 - 20 = 19, 19×3 + 40 = 97, 97×3 - 80 = 211
Wrong number is 99 and it should be replaced with 97.
Hence, option 3.




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