Q. Replace the incorrect term by the correct term in the given sequence

Explanation :

Replacing the incorrect term by correct term

Let’s solve this sequence problem step by step:

1. Original sequence:
3, 2, 7, 4, 13, 10, 21, 18, 31, 28, 43, 40

2. Analysis of odd-positioned numbers (1st, 3rd, 5th…):
3, 7, 13, 21, 31, 43
Differences: 4, 6, 8, 10, 12
Pattern: Each difference increases by 2

3. Analysis of even-positioned numbers (2nd, 4th, 6th…):
2, 4, 10, 18, 28, 40
Differences: 2, 6, 8, 10, 12
Problem: First difference is 2, breaking the pattern

4. Correction needed:
Starting from 3 (first number)
For consistent pattern, next number should create difference of 4
Therefore, second number should be 0 (not 2)
Because: 3 → 0 gives difference of 3
And: 0 → 4 gives difference of 4

5. After correction:
Odd terms differences: 4, 6, 8, 10, 12
Even terms differences: 4, 6, 8, 10, 12

Answer: (a) 0 is correct.

The sequence becomes perfect when 2 is replaced with 0, making both odd and even terms follow same pattern of differences increasing by 2.