The range of swim times is 5.6 hr. The range of a set of data is the difference between the highest and lowest values in the set. To find the range, first order the data from least to greatest. Then subtract the smallest value from the largest value in the set.
Every month that you make a partial payment, your credit card account will fall further and further past due. You will go from 30 to 60 to 90 days past due. This information will be reported on your credit file and your credit score will be lowered.
Unfortunately, the act of making the last payment will not have any impact on your credit score. You have accrued a significant amount of positive already just by making the payments on time and now this will show up on your report for several more years with no way to make a negative impact.