What will come in place of the question mark? 4, 7, 12, 19, 28, ?

Question

What will come in place of the question mark? 4, 7, 12, 19, 28, ?

1. A. 49
2. B. 36
3. C. 30
4. D. 39 (Correct answer)

Correct Answer

Option D — 39

Detailed Solution & Explanation

The correct answer is 39.

Key Points

• The gaps between consecutive terms increase by a fixed amount — a second-level (constant second difference) series.
• Series: 4, 7, 12, 19, 28, ?
• 7 − 4 = 3
• 12 − 7 = 5
• 19 − 12 = 7
• 28 − 19 = 9
• The differences are consecutive odd numbers (3, 5, 7, 9), so the next difference is 11:
• 28 + 11 = 39.
• when the first differences themselves form a simple sequence (here odd numbers), it is a series with a constant second difference of 2, which is the signature of a quadratic (n²-type) pattern.

Exam Tip

• these terms also equal n² + 3 (2²+3=7, 3²+3=12, 4²+3=19, 5²+3=28, 6²+3=39) — spotting the closed form is an instant cross-check.