don't use foreach
. Use a for loop
so you can relate it directly to your model:
for(int i=0; i< model.Questions.Count;i++)
{
model.Question[i].QuestionText
for(int j=0; j<model.Question[i].Answers.Count; j++)
{
@Html.RadioButtonFor(x => x.Question[i].Answers[j], model.Questions[i].QuestionID, new { @name = model.Questions[i].QuestionID})
}
}