Explanation

In this series, each number is formed by adding the square of a natural number (1^2, 2^2, 3^2, .....) to the preceding number.

• 15 + 1² = 16
• 16 + 2² = 20
• 20 + 3² = 29 ← should be 29, but given 30
• 29 + 4² = 45
• 45 + 5² = 70

So the correct sequence should be:

15, 16, 20, 29, 45, 70

Therefore, 30 is the incorrect number

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Last updated by NS on 01 MAY 2026

Explanation

This is a geometric progression (GP) where each term is multiplied by 3:

1, 3, 9, 27, 81, 243, 729, 2187

Formula:

Here:

• a = 1
• r = 3
• n = 8

So:

8th term = 2187

Last updated by NA on 2 MAY 2026

Explanation

Explanation

Series:

6, 3, 12, 6, 24, ___

Step 1: Find a pattern

• 6 → 3 (÷2)
• 3 → 12 (×4)
• 12 → 6 (÷2)
• 6 → 24 (×4)

So the pattern alternates:
÷2, ×4, ÷2, ×4, ...

Step 2: Next term

$$24÷2=12$$

$$Last\; updated\; by\; NA\; on\; 25-April-2026$$

Explanation

Sequence: 2, 1, 3, 4, 7, 11, ?

Observe the pattern:
Each term is the sum of the previous two terms

• 2 + 1 = 3
• 1 + 3 = 4
• 3 + 4 = 7
• 4 + 7 = 11
• 7 + 11 = 18