undefined power bi

Hi Eng-mohd if your sheet 1 and sheet 2 have the same structure,  and data for durations is in minutes (same in two sheets) possible solution (adjsust sheets / column names to your need)
1. Create new table 

CombinedTable = UNION(Sheet1, Sheet2)

2. Create measure

Persons_More_Than119Minutes =
CALCULATE(
COUNTROWS(DISTINCT(CombinedTable[ID])),
CombinedTable[Duration] > 119
)

Hi Eng-mohd ,

You can create a measure as below to get it, please find the details in the attachment.

Measure = 
VAR _sheet1 =
    CALCULATETABLE (
        VALUES ( 'Sheet1'[id] ),
        FILTER ( 'Sheet1', 'Sheet1'[duration time] > 119 )
    )
VAR _sheet2 =
    CALCULATETABLE (
        VALUES ( 'Sheet2'[id] ),
        FILTER ( 'Sheet2', 'Sheet2'[duration time] > 119 )
    )
VAR _tab =
    DISTINCT ( UNION ( _sheet1, _sheet2 ) )
RETURN
    COUNTROWS ( _tab )

Best Regards