Nancy gives her grandson, Sean, 20 acres of land

Nancy gives her grandson, Sean, 20 acres of land. Her tax basis in the land is $25,000. Nancy’s marginal tax

rate for the current year is 45%; her grandson’s is 25%. Its fair market value was $575,000 at the date of the transfer. If the gift tax rate is 40% and she has never made a gift in excess of $10,000 before this, what amount of gift tax will she pay? What is their net tax savings percentage as a family unit if Sean sells the land?   Would she be better off selling and leaving him the money or not selling?