Please Help!! I don't get how to calculate interest.. Use the credit card information below and the designated method of computing interest to fill in the blanks. (See image)

Adjusted Balance Method-
Interest $_
New Balance $_

Previous Balance Method-
Interest $_
New Balance $_

Daily Balance Method-
Interest $_
New Balance $_

Adjusted Balance Method:

Interest $__3.90

New Balance $__568.90

Explanation:

a) Data and Calculations:

Previous balance = $500

Purchases:

May 12   $25

May 22  100

May 30   50

Total   $175

Payment:

May 20 $110

Interest = $3.90 ($500 - $110)

New Balance $ = Adjusted balance + New Purchases + Interest

= $390 + $175 + $3.90

= $568.90

b) Based on the credit card information and using the adjusted balance method, you compute the finance charge (or interest) based on the previous balance of $500 from the end of the last billing cycle and subtract any payments and credits of $110 made during the current billing cycle.  This simply means that the new charges (purchases on the credit card) of $175made during the billing cycle are not factored into the adjusted balance before calculating interest.