Question: What is the missing number in the series: 3, 6, 11, 18, ...?

Options:

1. 25
2. 26
3. 27
4. 28

Correct Answer: 26

Solution:

The differences are 3, 5, 7, which increase by 2 each time. The next difference is 9, so 18 + 9 = 27.