Option Explicit
Sub Test()
Dim strPath As String
Dim strFile As String
Dim strFormula As String
strFile = "abc.xlsx"
strPath = "D:\Folder\Subfolder\"
If Right$(strPath, 1) <> "\" _
Then strPath = strPath & "\"
strFormula = "='%PATH%[%FILE%]korr'!RC"
strFormula = Replace$(strFormula, "%PATH%", strPath, Compare:=vbBinaryCompare)
strFormula = Replace$(strFormula, "%FILE%", strFile, Compare:=vbBinaryCompare)
ThisWorkbook.Worksheets("snt").Range("A1:B3").FormulaR1C1 = strFormula
End Sub