Maria Chavez makes custom mooring covers for boats in Tumpa, Florida. Each mooring cover is hand sewn to fit a particular boat. If covers are made for two or more identical boats, each successive cover generally requires less time to make. Chavez has been approached by a local boat dealer to make mooring covers for all of the boats sold by the dealer. Chavez has developed the following cost schedule for mooring covers made to fit 17-foot outboard power boats.
Mooring Covers Made Total Cost of Covers
1.................................................................... $ 675
2.................................................................... 1,275
3.................................................................... 1,815
4.................................................................... 2,310
5.................................................................... 2,775

Required:
Compute the following:
1. Marginal cost of second mooring cover.
2. Marginal cost of fourth mooring cover.
3. Marginal cost of fifth mooring cover.
4. Average cost if two mooring covers are made.
5. Average cost if four mooring covers are made.
6. Average cost if five mooring covers are made.