What number would replace question mark (?) in the series given below?
3, 8, 17, 32, 57, ?, 177
Correct Answer :
100
Solution :
The correct option is: 100.
To find the missing number in the given series, let us analyze the differences between consecutive terms:
First level of differences:
Now, let us find the differences between these first-level differences (the second level of differences):
Second level of differences:
If we look closely at the sequence of second differences (4, 6, 10, ...), we can observe a pattern in the differences between them (the third level of differences):
Third level of differences:
The differences in the third level are doubling (2, 4, ...). Following this pattern, the next third-level differences should be 8 and then 16.
Using this logic, we can work backwards to find the missing terms:
The next second-level difference:
The subsequent second-level difference:
Now, we find the next first-level differences by adding these values to the previous first-level differences:
The next first-level difference:
The subsequent first-level difference:
Finally, we calculate the missing term (?) in our original sequence:
The missing number replacing the question mark (?):
We can verify this by checking if it leads to the final number in the series (177) using the subsequent difference of 77:
Verification:
Since the calculations match the given sequence, the number that replaces the question mark is indeed 100.
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