\( \definecolor{colordef}{RGB}{249,49,84} \definecolor{colorprop}{RGB}{18,102,241} \)
Let \(X_1, X_2, X_3\) be the result of three coin flips, where \(X_i=1\) if the \(i\)-th coin lands on Head and \(0\) otherwise. Let \(S_3 = X_1 + X_2 + X_3\).
  1. What does \(S_3\) represent?
  2. What possible values can be taken by \(S_3\)?

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