Enabling averages over Sliced Dates

Enabling the information that the slicer has returned to interface with quick measures and calculations. For example, A user has selected a sliced date of 7 Oct 2017 - 21 Nov 2017. Data is shown for these 46 days. Now the trick being to then use this result of 46 days in a measure to create a weekly average over these 46 Days. Giving / 7 giving 6.6 weeks. This 6.6 weeks then would be dynamic based on the slicer. Unless I have missed something and this can be done now...