1. Frank's electric bill has a cycle day of the 3rd and a due date 8 days later with a one day grace period. What happens if Frank pays his electric bill on the 12th of the month?

The cycle day of Frank’s electric bill is the 3rd of the month. It is due 8 days after, which is the 11th of the month. A one-day grace period is given, which falls on the 12th of the month. If Frank pays his electric bill on the 12th of the month, he is still within the provided grace period and will not incur surcharges on his electric bill.

The answer is he won't be paying any late or penalty fee.

Grace period is usually given by the company as a form of goodwill towards the consumers who are late in paying their late bills.

Since on the 12th day is still considered within the one day grace period, Frank is not entitled to pay any additional amount from his usual charge of the bill (or any other form of penalties)