एक सिक्का इस प्रकार अभिनत है कि चित्त के आने की संभावना पट् के आने की संभावना की तीन गुना है। इस सिक्के को तब तक उछाला जाता है जब तक कि एक चित्त या तीन पट् दिख जाएँ। यदि \(\mathrm{X}\) सिक्के को उछालने क़ी संख्या को दर्शाता है, तो \(\mathrm{X}\) का माध्य है

Apply the relevant identity from the chapter and substitute the values established in the previous step, keeping the original constraint in view.

Use the simplified expression to isolate the unknown, then plug the result back into the question setup to confirm the working is internally consistent.

Cross-check against a boundary or limiting case. Both the dimensional balance and the qualitative behaviour at the extreme should agree with the candidate answer.

Combine the steps above to identify the correct option. The remaining choices each fail at least one of the consistency, dimensional, or boundary checks.