Jill's credit card was stolen. The thief charged a $900 kayak on the card before she reported it stolen.
a. How much of the thief's purchase is Jill responsible for?
b. Jill's average daily balance would have been $1,240 without the thief's purchase. What was the sum of her daily balances for the 30-day billing period? Explain.
c. The thief's purchase was on her daily balances for 10 out of the 30 days during the billing cycle. What was the sum of Jill's daily balances with the thief's purchase included?
d. What was the average daily balance with the thief's purchase included?