Which explains why the sequence 216, 12, 2/3 is arithmetic or geometric.
A. The sequence is geometric because it decreases by a factor of 6.
B. The sequence is arithmetic because it decreases by a factor of 6.
*C. The sequence is geometric because it decreases by a factor of 1/18.
D. The sequence is arithmetic because it decreases by a factor of 1/18.
C, because every time you multiply the preceding number by 1/18, you get the next number in the sequence. It's not D, because an arithmetic sequence would be 216-1/18 (a difference of 1/18) rather than it decreasing by a factor.
