In one sentence, describe what the following article is about:

With a tiered APR, the credit card company applies different rates to different parts of the balance. For example, it may charge 17 percent on balances up to $1,000 and 19 percent on balances above $1,000.00. If you have an outstanding balance of $1,500, you would pay 17 percent interest on the first $1,000 and 19 percent interest on the last $500. Figure out how many tiers apply to the outstanding amount at the end of your billing cycle. You need to figure out the DPR for each of those rates individually. So, for our example:  17 ÷ 365 results in a DPR of 0.047 for the first $1,000 of your balance. 19 ÷ 365 results in a DPR of 0.052 for the last $500 of your balance. The steps are essentially the same as those for fixed and variable rates, as you can see. But it's important that you remember to apply each step to the different tier rates. Assume that we’re calculating the monthly rate for January, which has 31 days.  0.047 x 31 = a monthly rate of 1.457 percent for the first $1,000 0.052 x 31 = a monthly rate of 1.612 percent for the last $500 Again, move decimal points two places to the left to convert percentages to numbers that can be multiplied.  $1,000 x 0.01457 = $14.57 of interest paid on the first $1,000 $500 x .01612 = $8.06 of interest paid on the last $500 $14.57 + $8.06 = $22.63 of interest paid on your outstanding balance of $1,500.

Summary:
Understand how tiered APRs work. Calculate the DPR for each tier. Multiply each DPR by the number of days in the month. Calculate the interest paid on your outstanding balance. Add the amounts together to find your total.