In the sequence of numbers 5, 8, 13, X, 34, 55, 89, ..... the value of ‘X’ is
- A20
- B21Correct
- C23
- D29
Explanation
The given sequence follows the logic of a Fibonacci series where each number is the sum of the two preceding numbers.
Starting from the beginning: 5 plus 8 equals 13. 8 plus 13 equals 21. 13 plus 21 equals 34. 21 plus 34 equals 55. 34 plus 55 equals 89.
By applying this pattern, the value of X is 8 plus 13, which equals 21. Therefore, option B is the correct answer.
Related questions
More UPSC Prelims practice from the same subject and topic.
- Prelims 1999GS1science-and-technology
In eye donation, which one of the following parts of donor’s eye is utilised?
- Prelims 1999GS1science-and-technology
Consider the following statement: An ordinary light bulb has a rather short life because the I. filament wire is not uniform. II. bulb cannot be evacuated completely. III. wires supporting the filamen…
- Prelims 1999GS1science-and-technology
Match the hormones in List I with items in List II and select the correct answer using the codes given below the Lists: List I I. Adrenaline II. Estrogen III. Insulin IV. Pheromones List II A) Anger, …
- Prelims 1999GS1science-and-technology
Match List I (Drugs / Chemicals) with List II (Their uses) and select the correct answer using the codes given below the Lists: List I I. Atropine II. Ether III. Nitro-glycerine IV. Pyrethrin List II …
- Prelims 1999GS1science-and-technology
Match List I (Quantity) with List II (Units) and select the correct answer using the codes given below the Lists: List I List II I. High speed A) Mach II. Wavelength B) Angstrom III. Pressure C) Pasca…
- Prelims 1999GS1science-and-technology
For which one of the following is capillarity not the only reason?