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A regular die is rolled such that if the number on the die is odd, then a coin is tossed once. If the number on the die is even, the coin is tossed twice. Write the sample space for this experiment. Find P(getting a number 2 and two tails).

User Jad Chaar
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Final answer:

The sample space for the experiment with both the die roll and coin tosses includes 18 outcomes, such as 1H, 1T, 2HH, 2HT, and so on. The probability of rolling a 2 on the die and getting two tails (2TT) from the coin tosses is 1/18, as there is only one such outcome in the complete sample space.

Step-by-step explanation:

Experiment Sample Space and Probability Calculation

When performing an experiment where a regular die is rolled and depending on the result a coin is tossed either once or twice, we have a compound experiment with two stages, and the sample space needs to account for all possible outcomes from both stages of the experiment.

Considering a six-sided die with faces {1, 2, 3, 4, 5, 6}, the sample space for rolling the die is this set of numbers. For each odd number (1, 3, and 5), the coin is tossed once, with possible outcomes being {H, T}. For each even number (2, 4, and 6), the coin is tossed twice, with possible outcomes being {HH, HT, TH, TT}. Combining these, we have a sample space for this experiment as follows:


  • 1H, 1T

  • 2HH, 2HT, 2TH, 2TT

  • 3H, 3T

  • 4HH, 4HT, 4TH, 4TT

  • 5H, 5T

  • 6HH, 6HT, 6TH, 6TT

Now, to find the probability of getting a number 2 and two tails (2TT), we can calculate it by considering that there is only one outcome of 2TT in the sample space, and there are a total of 12 possible outcomes from tossing the coin (1 toss for each odd number and 2 tosses for each even number), resulting in a sample space of 18 outcomes when combined with the die roll. Hence, the probability P(getting a number 2 and two tails) = 1/18.

User Daf
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DIE SAMPLE SPACE={1,2,3,4,5,5} = 6 possible outcomes
COIN SAMPLE SPACE = {H,T} = 2

P(rolling 2) = 1/6 = 0.1667
P(Tail) = 1/2 = 0.5
P(H AND T) = 1/2 x 1/2 = 1/4 = 0.25
P(Even ∩ T ∩ T) = 0.1667 x 0.5 x 0.5 = 0.04166

User Crivella
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