Question
An experiment consists of tossing a coin and then throwing it second time if a head occurs. If a tail occurs on the first toss, then a die is rolled once. Find the sample space.
Solution
A coin is tossed, the sample space, 
A coin is tossed again, the sample space,
A die is rolled, the sample space,
If a head comes up in the first toss, the coin is tossed again. If a tail comes up in the first toss, a die is rolled.
∴ The combined sample space,
S = {HH, HT. T1, T2, T3, T4, T5, T6}
