What will come in place of the question mark (?) in the following number series? 4, 8, 12, 20, ? MCQ with Answer and Explanation

What will come in place of the question mark (?) in the following number series? 4, 8, 12, 20, ?
A. 36
B. 28
C. 24
D. 32
Answer: Option D
Solution (By JKSSB Mock Tests)
The pattern alternates: +4, ×2? No, 4+4=8, 8+4=12, 12+8=20. Actually, it's adding consecutive even numbers: +4, +4, +8. But more precisely: 4+4=8, 8+4=12, 12+8=20, 20+12=32? Let's re-evaluate: The differences are 4, 4, 8, 12. Not a clear pattern. A better pattern: each term is the sum of the previous two terms? 4+8=12, 8+12=20, 12+20=32. Yes, this is a Fibonacci-like series. The next term is 12+20=32.

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Practice More Number Series Questions

Question #1
What will come in place of the question mark (?) in the following number series? 3, 5, 9, 17, ?
A. 33
B. 31
C. 35
D. 29

Correct Answer: Option A


Explanation:
Each term is obtained by multiplying by 2 and subtracting 1. (3×2)-1=5, (5×2)-1=9, (9×2)-1=17. The next term is (17×2)-1=33.

This question belongs to: Reasoning Number Series
Question #2
What will come in place of the question mark (?) in the following number series? 5, 17, 33, 53, 77, ?
A. 97
B. 99
C. 101
D. 105

Correct Answer: Option D


Explanation:
The differences are: 12, 16, 20, 24. These are increasing by 4. The next difference is 28. Therefore, 77+28=105.

This question belongs to: Reasoning Number Series
Question #3
What will come in place of the question mark (?) in the following number series? 3, 10, 21, 36, 55, ?
A. 80
B. 76
C. 78
D. 74

Correct Answer: Option C


Explanation:
The differences are: 7, 11, 15, 19. These are increasing by 4. The next difference is 23. Therefore, 55+23=78.

This question belongs to: Reasoning Number Series