Please help with this question:

The City of Deshields establishes an Internal Service Fund (ISF) to provide limousine services to all City agencies. The Mayors office activity is recorded in the Citys General Fund. The ISF has concluded that each of its limousines should be billed out to the City at a rate of $150 per hour. Based on this information, prepare journal entries to record the following transactions in all of the appropriate City funds.

what are the entries in the ISF, General Fund and Enterprise fund(EF) for the following:

The head of the Citys Electric Utility Enterprise Fund and the City Controller attend a ribbon cutting ceremony celebrating the opening of the new electric plant. Both limousines were used for 7 hours each. The ISF bills the Mayors office and the EF for the service.

what is the debit entry that ISF account enters for its billing of enterprise fund? Is it accounts receivable from EF or Due from EF?

what is the credit entry enterprise fund enters when receives the bill from ISF? is it accounts payable to ISF or due to ISF?