Question 4 of 10 Ronnie has a credit card that uses the previous balance method The opening balance of one of his 30-day billing cycles was 4790 but that was his balance for only the first 4 days of the billing cycle, because he then paid off his entire balance and didn't make any new purchases. If his credit card's APR is 15% which of these expressions could be used to calculate the amount Ronnie was charged in interest for the billing cycle? A ((0.15)/(365)cdot 30)((4cdot 4790+26cdot 0)/(30)) B ((0.15)/(365)cdot 30)( 4790) C ((0.15)/(365)cdot 30)( 0) D ((0.15)/(365)cdot 30)((4cdot 0+26cdot 4790)/(30))

To calculate the amount Ronnie was charged in interest for the billing cycle, we need to use the previous balance method. This method calculates the interest based on the balance at the beginning of the billing cycle.<br /><br />Given information:<br />- Opening balance: $4790<br />- APR: 15%<br />- Billing cycle: 30 days<br />- Ronnie paid off his entire balance after 4 days, so the balance for the remaining 26 days was $0.<br /><br />Let's analyze the options:<br /><br />A. $(\frac {0.15}{365}\cdot 30)(\frac {4\cdot \$ 4790+26\cdot \$ 0}{30})$<br /> This expression correctly calculates the average daily balance for the billing cycle and then multiplies it by the daily interest rate and the number of days in the billing cycle.<br /><br />B. $(\frac {0.15}{365}\cdot 30)(\$ 4790)$<br /> This expression only uses the opening balance and does not account for the fact that the balance was $0 for the remaining 26 days.<br /><br />C. $(\frac {0.15}{365}\cdot 30)(\$ 0)$<br /> This expression incorrectly assumes that the balance was $0 for the entire billing cycle.<br /><br />D. $(\frac {0.15}{365}\cdot 30)(\frac {4\cdot \$ 0+26\cdot \$ 4790}{30})$<br /> This expression incorrectly calculates the average daily balance by swapping the number of days with the balance values.<br /><br />Therefore, the correct expression to calculate the amount Ronnie was charged in interest for the billing cycle is option A:<br />$(\frac {0.15}{365}\cdot 30)(\frac {4\cdot \$ 4790+26\cdot \$ 0}{30})$