What is the average percentage of the yellow section that is
backed up in each day
of the four day cycle (i.e., assuming the 15% change is uniformly distributed)?
| Day 1 | 100%, since this is its partial full backup. |
| Day 2 | 15%, since this is the daily change rate. |
| Day 3 | 27.75%, computed
as 30% - (15% of 15%) = 30% - 2.25%. The first term is the maximum incremental size (if the overlap was 0): 2 * 15%. The second term is the overlap: the part of the 15% backed up on day 2 that changed again on day 3. |
| Day 4 | 45% - (15% of 27.75%) = 45% - 4.16% = 40.84% |