Direction(1-5): Insert the missing number.
1. 16, 33, 65, 131, 261, (....)
A. 523
B. 521
C. 613
D. 721
Answer - Option A
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, (....)
Answer - Option B
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, (....)
Answer - Option C
Explanation -
Numbers are [latex]{1}^{2}, {2}^{2}, {3}^{2}, {4}^{2}, {5}^{2}, {6}^{2}, {7}^{2}.[/latex]
So, the next number is [latex]{8}^{2} = 64.[/latex]
4. 2, 4, 12, 48, 240, (....)
A. 960
B. 1440
C. 1080
D. 1920
Answer - Option B
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, (....)
Answer - Option B
Explanation -
There are two series (8, 11, 14, 17, 20) and (7, 12, 17, 22) increasing by 3 and 5 respectively.