Business Week

Hello,

I have a spreadsheet (attached) containing 3 columns, week commencing (c), week ending (d) and business week (e). The question is can a user enter a date in one cell (b4) and have the next cell (b5) return the corresponding business week, I have come up with a couple of solutions involving hidden columns but was wondering if there is a way to do all of this in one cell.

Thanks