Spreadsheet

Hello,

I'm currently working on a spreadsheet for a timesheet. I want to format a cell to display the date of a certain day of the week. e.g. I would cell B20 to only display the date of Monday for the current week that the sheet is opened. If it the current week is 5/11 - 5/17 and I want B20 to only display the date for Wednesdays so cell B20 should display 5/13. Is this possible? Even if I open the sheet on the Friday I still want B20 to display the date for Wednesday. All help would be greatly appreciated.