Question

A coin is tossed repeatedly until a tail comes up for the first time. Write the sample space for this experiment.

Answer 1

In this experiment, a tail (T) may come up on the first throw, the second throw, the third throw and so on, until T is obtained.
This process continues indefinitely.
Hence, the sample space of this experiment is given by
S = {T, HT, HHT, HHHT, HHHHT, HHHHHT, ...}