Create new table applying cartesian logic

jeronimo2334  Updated to meet that additional requirement

Place the following M code in a blank query to see the steps for your expected table. 

See it all at work in the attached file.

let
    Source = ExamsT,
    #"Added Custom" = Table.AddColumn(Source, "Custom", each StudentsT),
    #"Expanded Custom" = Table.ExpandTableColumn(#"Added Custom", "Custom", {"Student"}, {"Student"}),
    #"Changed Type" = Table.TransformColumnTypes(#"Expanded Custom",{{"Student", type text}}),
    #"Merged Queries" = Table.NestedJoin(#"Changed Type", {"Exam", "Student"}, ResultsT, {"Exam", "Student"}, "ResultsT", JoinKind.LeftOuter),
    #"Expanded ResultsT" = Table.ExpandTableColumn(#"Merged Queries", "ResultsT", {"Result"}, {"Result"}),
    #"Replaced Value" = Table.ReplaceValue(#"Expanded ResultsT",null,"Not taken",Replacer.ReplaceValue,{"Result"}),
    #"Sorted Rows" = Table.Buffer(Table.Sort(#"Replaced Value",{{"Exam", Order.Ascending}, {"Student", Order.Ascending}, {"Result", Order.Descending}})),
    #"Removed Duplicates" = Table.Distinct(#"Sorted Rows", {"Exam", "Student"})
in
    #"Removed Duplicates"

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