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In the following number series only one number is wrong. Find out the wrong number
15 17 16 19 17 20 18 21
  • a)
    17
  • b)
    19
  • c)
    20
  • d)
    16
  • e)
    None of the above
Correct answer is option 'A'. Can you explain this answer?
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Most Upvoted Answer
In the following number series only one number is wrong. Find out the...
Analyzing the Number Series
The given number series is:
15, 17, 16, 19, 17, 20, 18, 21
Let's break down the pattern in the series.
Observing the Pattern
- The series alternates between increasing and decreasing numbers.
- Odd-indexed positions (1st, 3rd, 5th, 7th): 15, 16, 17, 18
- Even-indexed positions (2nd, 4th, 6th, 8th): 17, 19, 20, 21
Odd-Indexed Positions
- 1st: 15
- 3rd: 16 (increased by 1 from 15)
- 5th: 17 (increased by 1 from 16)
- 7th: 18 (increased by 1 from 17)
This sequence is consistent; each number increases by 1.
Even-Indexed Positions
- 2nd: 17
- 4th: 19 (increased by 2 from 17)
- 6th: 20 (increased by 1 from 19)
- 8th: 21 (increased by 1 from 20)
Here, we notice a discrepancy. The second number (17) should follow a consistent increasing pattern.
Finding the Anomaly
- The expected pattern would suggest that after 17, the next number should increase by 2 (to 19), but the next number is 19.
- However, the following number, which is 20, diverges from the expected pattern, as it should have been a 18 (increasing by 1 from 17).
Conclusion
Given that the number 17 appears in both the odd and even positions without a valid pattern in the even series, it disrupts the flow. Hence, 17 is the redundant number in this series.
Thus, the wrong number is 17, making option 'A' the correct answer.
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Community Answer
In the following number series only one number is wrong. Find out the...
15 + 3 = 18
18 - 2 = 16
16 + 3 = 19
19 - 2 = 17
17 + 3 = 20
20 - 2 = 18
18 + 3 = 21
Hence, 17 is the wrong number in the series
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In each of the following questions the series begins with an unnumbered figure on the extreme left. One and only one of the five numbered figures in the series do not fit into the series. The two unnumbered figures one each on the extreme left and the extreme right fit into the series. You have to take as many aspects into account as possible of the figures in the series and find out the one and only one of the five numbered figures which does not fit into the series. The number of that figure is the answer.Study the following question.In this question the number of lines in the figures goes on increasing one from left to right. If we go by this aspect of the number of lines’ only then there is no wrong figure in the series. But if we also consider the ‘manner’ in which the ‘number of lines’ in the figures goes on increasing from left to right we come to know that the figure No. 4 does not fit into the series. Therefore, 4 is the answer.

In each of the following questions series begins with unnumbered figure on the extreme left. One and only one of the five numbered figures in the series do not fit into the series. The two unnumbered figures one each on the extreme left and the extreme right fit into the series. You have to take as many aspects into account as possible of the figures in the series and find out the one and only one of the five numbered figures which does not fit into the series. The number of that figure is the answer.In this question the number of lines in the figures goes on increasing one from left to right. If we go by this aspect of number of lines' only then there is no wrong figure in the series. But if we also consider the 'manner' in which the 'number of lines' in the figures goes on increasing from left to right we come to know that the figure No. 4 does not fit into the series. Therefore, 4 is the answer.Solve the following question accordingly

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In the following number series only one number is wrong. Find out the wrong number15 17 16 19 17 20 18 21a)17b)19c)20d)16e)None of the aboveCorrect answer is option 'A'. Can you explain this answer?
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