Return a corresponding value from another table based on calculated measure

Anonymous 
Not enough information but can you try the following meaure:

RateMeasure =
VAR __AgeSelected =
    MAX ( ThisTable[MachineAge] )
RETURN
    CALCULATE (
        MAX ( AgeTablename[Buyback rate %] ),
        AgeTablename[Age] = __AgeSelected
    )

 Replace the table and columns names as per your model
 

Hey! The measure that you posted was unfortunately not working directly (blame is on me, I didn't provide enough information). Luckily I got the measure working, adding the rounddown function on the age and deleting the Max statement from "var age" function was the key as shown below.  

Machine age := 
var age = (MAX(vDimCalendar[Date]) - MAX(Buybacks[Delivered (month/year)])) / 365  * 12
return
ROUNDDOWN(age, 0)
---------------------------------------------------------------------------------------------
Buy-back policy rate := 
VAR __AgeSelected =
     'Measures table'[Machine age] 
RETURN
    CALCULATE (
        MAX ( 'Buyback policy rates'[Trade-in] ),
        'Buyback policy rates'[Month] = __AgeSelected
    )