Complete the series: 22, 33, 46, 61, 78, ?

Question

Complete the series: 22, 33, 46, 61, 78, ?

1. A. 86
2. B. 97 (Correct answer)
3. C. 90
4. D. 79

Correct Answer

Option B — 97

Detailed Solution & Explanation

The correct answer is 97.

Key Points

• This is a difference series where the gaps grow by a fixed amount.
• Series: 22, 33, 46, 61, 78, ?
• 33 − 22 = 11
• 46 − 33 = 13
• 61 − 46 = 15
• 78 − 61 = 17
• The differences are consecutive odd numbers (11, 13, 15, 17), so the next difference is 19:
• 78 + 19 = 97.
• when the first differences increase by a constant (here +2 each time), the series is quadratic.
• Compute the differences first, confirm they form a simple pattern, then extend it.

Exam Tip

• these terms also equal n² + a constant pattern-wise; spotting that differences are consecutive odd numbers is the fastest route to the next term.