In the series 8, 11, 19, 23, 32, ?, determine the next number that correctly continues the pattern.

Difficulty: Medium

Correct Answer: 37

Explanation:


Introduction / Context:
This sequence alternates between relatively small and moderately larger jumps, which suggests that the differences between consecutive terms follow their own pattern in two intertwined streams. Identifying this alternating structure allows us to predict the next increment and therefore the next term accurately.


Given Data / Assumptions:

  • The series is: 8, 11, 19, 23, 32, ?
  • We must find the next term at the end.
  • We assume a consistent rule, likely in the pattern of differences.
  • The differing sizes of the jumps hint at alternating small and large increments.


Concept / Approach:
We compute the differences between consecutive terms and then examine those differences themselves as a new sequence. If the differences alternate between two simple progressions (for example 3, 4, 5 and 8, 9, 10), we can extend the appropriate progression to find the next difference. Adding this difference to the last known term yields the next number in the original series.


Step-by-Step Solution:
Step 1: Compute the differences between consecutive terms. 11 - 8 = 3. 19 - 11 = 8. 23 - 19 = 4. 32 - 23 = 9. Step 2: Group the differences into two sequences: small and large. Small differences: 3, 4, ... Large differences: 8, 9, ... Step 3: Notice that the small differences increase by 1: 3 → 4, so the next small difference should be 5. Step 4: Notice that the large differences also increase by 1: 8 → 9, so the next large difference would be 10, but this is for the step after our missing term. Step 5: The pattern of differences is therefore 3, 8, 4, 9, 5, 10, ... applied alternately. Step 6: We have already used 3, 8, 4, 9; the next difference to add is 5. Step 7: Add 5 to the last known term: 32 + 5 = 37.


Verification / Alternative check:
Write out the extended series including the next term: 8, 11, 19, 23, 32, 37. The differences are 3, 8, 4, 9, 5. This matches the pattern 3, 8, 4, 9, 5, and if we continued, we would expect a difference of 10 next, consistent with the observed rule. The alternating sequences of small and large differences, each increasing by 1, confirm that 37 is indeed the correct extension.


Why Other Options Are Wrong:
If we chose 39, the new difference would be 7, which does not fit either the small (3, 4, 5, ...) or large (8, 9, 10, ...) progression. Choosing 47 or 49 produces even larger differences that do not continue either of the sub sequences. Thus those values break the carefully alternating structure that the existing terms display.


Common Pitfalls:
A frequent mistake is to look only at the overall growth and attempt to guess a single difference sequence, which appears irregular. Another is to consider just the first two increments and assume a simple pattern, ignoring the alternation. Looking at all differences in order and noticing the alternating small and large increases is essential for solving this type of problem correctly.


Final Answer:
Maintaining the alternating difference pattern of 3, 8, 4, 9, 5, 10, the next term after 32 is 37.

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