Question a: 3cm
question b: 8cm
question c: 12cm
(could be wrong)
Your question doesn't say what are the options, but we can make some reasoning.
The average daily balance method is based, obviously, on the <span>average daily balance, which is the average balance for every day of the billing cycle. Therefore, in order to calculate the average daily balance, you need to sum the balance of every day and then divide it by the days of the billing cycle.
In your case:
ADB = (9</span>×2030 + 21×1450) / 30 = 1624 $
Now, in order to calculate the interest, you should first calculate the daily rate, since APR is usually defined yearly, and therefore:
rate = 0.23 ÷ 365 = 0.00063
Finally, the expression to calculate the interest could be:
interest = ADB × rate × days in the billing cycle
or else:
<span>interest = ADB × APR ÷ 365 × days in the billing cycle
In your case:
interest = 1624 </span>× 0.23 ÷ 365 × 30
= 30.70 $
The explicit formula is D. -4n + 15.
