Arithmetic sequence: 10, 14, 18, 22, 26

Check the first differences: if they're constant, add the difference once more for the next term. The correct answer is 30. Traps to avoid: 34 comes from the "doubled step" error; 22 comes from the "subtracted step" error; 42 comes from the "added whole span" error; 26 comes from the "repeated last" error.