Aptitude - Odd Man Out and Series

Exercise : Odd Man Out and Series - Missing No.
Directions to Solve
Insert the missing number.

1.
16, 33, 65, 131, 261, (....)
523
521
613
721
Answer: Option
Explanation:

Each number is twice the preceding one with 1 added or subtracted alternatively.

So, the next number is (2 x 261 + 1) = 523.


2.
10, 5, 13, 10, 16, 20, 19, (....)
22
40
38
23
Answer: Option
Explanation:
There are two series (10, 13, 16, 19) and (5, 10, 20, 40), one increasing by 3 and the other multiplied by 2.

3.
1, 4, 9, 16, 25, 36, 49, (....)
54
56
64
81
Answer: Option
Explanation:

Numbers are 12, 22, 32, 42, 52, 62, 72.

So, the next number is 82 = 64.


4.
2, 4, 12, 48, 240, (....)
960
1440
1080
1920
Answer: Option
Explanation:

Go on multiplying the given numbers by 2, 3, 4, 5, 6.

So, the correct next number is 1440.


5.
8, 7, 11, 12, 14, 17, 17, 22, (....)
27
20
22
24
Answer: Option
Explanation:

There are two series (8, 11, 14, 17, 20) and (7, 12, 17, 22) increasing by 3 and 5 respectively.