Question 8 of 10 Trina has a credit card that uses the adjusted balance method. For the first 10 days of one of her 30-day billing cycles.her balance was 780 She then made a purchase for 170 so her balance jumped to 950, and it remained that amount for the next 10 days. Trina then made a payment of 210 so her balance for the last 10 days of the billing cycle was 740 If her credit card's APR is 17% which of these expressions could be used to calculate the amount Trina was charged in interest for the billing cycle? A. ((0.17)/(365)cdot 30)((10cdot 780+10cdot 950+10cdot 740)/(30)) B ((0.17)/(365)cdot 30)( 570) C. ((0.17)/(365)cdot 30)((10cdot 780+10cdot 950+10cdot 210)/(30)) D. ((0.17)/(365)cdot 30)( 780)

To calculate the amount Trina was charged in interest for the billing cycle, we need to use the adjusted balance method. The adjusted balance method calculates the average daily balance by taking the sum of the daily balances for each day in the billing cycle and dividing it by the number of days in the billing cycle.<br /><br />Given information:<br />- Trina's credit card uses the adjusted balance method.<br />- For the first 10 days, her balance was $780.<br />- She made a purchase for $170, so her balance jumped to $950, and it remained that amount for the next 10 days.<br />- Trina made a payment of $210, so her balance for the last 10 days of the billing cycle was $740.<br />- The credit card's APR is 17%.<br /><br />To calculate the amount Trina was charged in interest, we can use the following expression:<br /><br />$(\frac{0.17}{365} \cdot 30) \cdot \frac{10 \cdot \$780 + 10 \cdot \$950 + 10 \cdot \$740}{30}$<br /><br />This expression represents the following steps:<br />1. Calculate the daily interest rate by dividing the APR (17%) by the number of days in a year (365).<br />2. Multiply the daily interest rate by the number of days in the billing cycle (30).<br />3. Calculate the average daily balance by taking the sum of the daily balances for each day in the billing cycle (10 days at $780, 10 days at $950, and 10 days at $740) and dividing it by the number of days in the billing cycle (30).<br /><br />Therefore, the correct answer is option A.