[Solved]-How to update my model code using LINQ-LINQ,C#

var selectedvalues = model
                     .questions
                     .select(q => q.selectedanswer);

foreach (var x in evalvm
                  .questions
                  .selectmany(q => q.answers)
                  .where(answer => selectedvalues.contains(answer.id.tostring())))                    
  x.isselected = "checked";