Guadalupe's credit card has an apr of 23% calculated on the previous monthly balance and a minimum payment of 2% starting the month after the first purchase her credit card record for the last 7 months is shown in the table below how are her finances charges calculated

To find the finance charge you multiply the balance times 0.23 / 12 .

To find the interest charge to an account, you have to multiply the balance by the percent rate (APR). 

The problem in this case is that interest is charged monthly, but the rate is yearly.

To fix this problem, just divide the rate by 12.  
0.23 / 12