A coin is tossed and a marble is drawn from a jar containing 12 marbles numbered 1 to 12. Find the probability of getting either heads or tails on the coin and picking a marble which shows a prime number.

The independent events of flipping a coin and drawing a marble mean the individual probabilities must be multiplied, but the outcome of heads or tails is a certainty (1) for the specific side chosen. A jar of 12 marbles contains the prime numbers 2, 3, 5, 7, and 11, giving exactly 5 favorable marbles. The probability of picking a prime marble is 5/12, and multiplying this by 1 yields 5/12.

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