Given:
Previous balance: 5,834.52
payment: 150
new transaction: 325
APR 20.4%
(20.4% / 360) * 30 = 1.7%
5,834.53 - 150 = 5,684.53
5,684.53 * 101.7% = 5,781.17 *Only the revolving amount is subject to the interest rate.
5,781.17 + 325 = 6,106.17
David's new balance will be B. 6,106.17