翻译一道英文出的数学题

翻译一道英文出的数学题
Phillip charged $400 worth of goods on his credit card. On his first bill, he was not charged any interest, and he made a payment of $20. He then charged another $18 worth of goods. On his second bill a month later, he was charged 2% interest on his entire unpaid balance. How much interest was Phillip charged on his second bill?
A.$8.76
B.$7.96
C.$7.60
D.$7.24
E.$6.63