Answer:
$2.66
Step-by-step explanation:
Since there are 31 day sin May, and the question doesn't specify any fixed billing cycle, we must calculate the billing cycle using 31 days:
Average daily balance = [($0 x 1) + ($100 x 19) + ($300 x 12)] / 31 days = $5,500 / 31 = $177.42
finance charge for the month of May = average daily balance x APR/12 = $177.42 x 18%/12 = $177.42 x 1.5% = $2.66
Some credit cards use fixed billing cycles, e.g. 30 days for every month, but if we are not given that information we have to assume that the billing cycle starts in day 1 and ends in the last day of the month.
