The sequence is arithmetic and the common difference is 9.
Work Step by Step
When a pattern is observed in the sequence the sequence is said to be arithmetic. In an arithmetic sequence, the difference between consecutive terms is constant. The sequence is given: 11, 20, 29, 38, ... Difference of first and second term: 20-11=9 Difference of second and third term: 29-20=9 Difference of third and fourth term: 38-29=9 Therefore the sequence is arithmetic as the common difference of the consecutive terms is constant which is 9.