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I need an explanation on how to find the probability that you will roll an even number exactly 5 times when you roll a six-sided number cube 10 times.

a) To calculate the probability, divide the number of successful outcomes by the total number of possible outcomes.
b) To calculate the probability, use the binomial probability formula.
c) The probability is 1/2 because there are two possible outcomes (even or odd).
d) The probability is 5/10, which simplifies to 1/2.

1 Answer

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Final answer:

To calculate the probability of rolling an even number exactly 5 times when rolling a six-sided die 10 times, use the binomial probability formula. So the correct option is b.

Step-by-step explanation:

To find the probability that you will roll an even number exactly 5 times when you roll a six-sided number cube 10 times, you should use the binomial probability formula. In this situation, each roll of the die represents a Bernoulli trial with two possible outcomes - rolling an even number (success) or not (failure).

The probability of success (rolling an even number) is 1/2 since there are three even numbers (2, 4, 6) out of six possible outcomes.

To calculate the exact probability of 5 successes (even numbers) in 10 trials, use the binomial probability formula:


P(X = k) = C(n, k) × p^k × (1-p)^(n-k)


Where:

C(n, k) is the combination of n items taken k at a time.

p is the probability of a single success (1/2 for an even number).

n is the number of trials (10 in this case).

k is the number of successes (5 in this case).


Using this formula, calculate C(10, 5), which is the number of ways to choose 5 successes out of 10 trials.

Then, multiply this by the probability of getting 5 even numbers raised to the 5th power, and the probability of not getting an even number (1-1/2 or 1/2) raised to the 5th power since there are 5 trials where an even number is not rolled.

The resulting number is the probability of exactly 5 even numbers in 10 rolls of the die.

So the correct option is b.

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