Rick held a fundraiser and is figuring out who still owes money. He marked on a sheet how much everyone has promised to contribute, but he forgot to note how much some people had actually paid. Altogether, everyone has promised to contribute $400, and Rick has actually received $285.  Sally, Amy, Derek, and Carl all still owe money. Sally and Carl both owe equal amounts, Amy owes $30, and Derek owes half as much as Amy. How much, in dollars, do Sally and Carl each owe?