Question Details

What number should replace the question mark (?)?


5, 12, 23, 50, 14, ?

Options

A

415

B

430

C

488

D

450

Show Answer

Correct Answer :

Option C

488

Solution :

The correct answer is 488.

Note on the Sequence:
The given sequence contains a typographical error in the fifth term. The number "14" is a print typo for "141". The correct mathematical sequence is:
5, 12, 23, 50, 141, ?

Let us analyze the relationship between successive terms by looking at their differences.

Step 1: Find the first-level differences
Calculate the difference between each consecutive pair of numbers:
12 - 5 = 7
23 - 12 = 11
50 - 23 = 27
141 - 50 = 91
So, the sequence of first-level differences is: 7, 11, 27, 91.

Step 2: Find the second-level differences (differences of differences)
Calculate the differences between the successive numbers in the first-level difference sequence:
11 - 7 = 4
27 - 11 = 16
91 - 27 = 64
The resulting second-level differences are: 4, 16, 64.

Step 3: Identify the pattern in the second-level differences
Notice that the numbers 4, 16, and 64 are consecutive powers of 4:
4 1 = 4
4 2 = 16
4 3 = 64

Step 4: Determine the next term
Following this geometric pattern, the next second-level difference must be:
4 4 = 256
To find the next first-level difference, add 256 to the previous difference (91):
91 + 256 = 347
Finally, add this difference to the fifth term (141) to get the missing term in the sequence:
141 + 347 = 488

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