1 10 7 20 13 30 19

• A. 26 40
• B. 40 50
• C. 40 25
• D. 29 36
• E. 25 31

Answer: (C)

Here, every other number follows a different pattern. In the first series, 6 is added to each number to arrive at the next. In the second series, 10 is added to each number to arrive at the next.