How to store the max date from a slicer as a new metric? (Or workaround it)

[Skunkworked]

Hello all, 

In a report I'm building, I'm attempting to create a couple of measures based on data similar to that in the below table. These measures, both counts, can be called Hikes Started and Hikes Completed. 

As a requisite: once a hike is completed, it is no longer counted as a hike start.

For the sample dataset below (and based on a selected date range of 1/3 - 3/31), each metric should be calculated as follows, based on this methodology:

- Hikes Completed (yellow) = 2  

- Hikes Started (green) = 3 [since the completed hikes no longer count as 'starts', and the completion date of these hikes is beyond my maximum date in the slicer]

I've been able ot replicate this calculation very easily in Excel, however, my solution there is based on the fact that i can i can easily reference the max date in the slicer.

Can anyone recommend any method by which I could either:
- A) create the two above-mentioned metrics (Hikes Started & Hikes Completed), or 
- B) store the Max date chosen in the slicer as a metric?

Thanks in advance!

[v-chuncz-msft · Accepted solution]

@Skunkworked,

Add a calendar table and use measures as shown below.

Hikes Completed =
CALCULATE (
    COUNTROWS ( Table1 ),
    Table1[Hike Complete Date] IN ALLSELECTED ( 'Calendar'[Date] )
)

Hikes Started =
VAR d =
    MAX ( 'Calendar'[Date] )
RETURN
    CALCULATE (
        COUNTROWS ( Table1 ),
        Table1[Hike Start Date] IN ALLSELECTED ( 'Calendar'[Date] ),
        Table1[Hike Complete Date] > d
    )