Two angles ∠QPR and ∠RPS share the common arm PR and are placed next to each other so that ∠QPR+∠RPS=150∘.
(i) Explain why ∠QPR and ∠RPS are called adjacent angles.
(ii) Using logical reasoning, decide whether the rays PQ and PS can lie on the same straight line. Give a clear justification for your answer.
(iii) State what special name (if any) can be given to the pair ∠QPR and ∠RPS. Support your statement with reasons.