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Last year, Melissa came in 22nd place in her school's Spelling Bee. This year, she plans to win 11st place. She compiled a long list of words to study, 49%49\% of which have a Latin root.\newlineIf Melissa randomly chooses a word to study from the list 55 different times this month, what is the probability that exactly 22 of the words have a Latin root?\newlineWrite your answer as a decimal rounded to the nearest thousandth.\newline____\newline

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Q. Last year, Melissa came in 22nd place in her school's Spelling Bee. This year, she plans to win 11st place. She compiled a long list of words to study, 49%49\% of which have a Latin root.\newlineIf Melissa randomly chooses a word to study from the list 55 different times this month, what is the probability that exactly 22 of the words have a Latin root?\newlineWrite your answer as a decimal rounded to the nearest thousandth.\newline____\newline
  1. Find Probability Latin Root: First, we need to find the probability of choosing a word with a Latin root. Since 49%49\% of the words have a Latin root, the probability is 0.490.49 for each pick.
  2. Calculate Not Latin Root: Now, we calculate the probability of not choosing a word with a Latin root, which is 10.49=0.511 - 0.49 = 0.51.
  3. Binomial Probability Formula: We're looking for the probability of exactly 22 words having a Latin root out of 55 picks. This is a binomial probability problem, where we use the formula P(X=k)=(nk)(pk)((1p)(nk))P(X=k) = \binom{n}{k} \cdot (p^k) \cdot ((1-p)^{(n-k)}), where nn is the number of trials, kk is the number of successes, and pp is the probability of success.
  4. Calculate 55 Choose 22: Let's calculate "55 choose 22" which is the number of ways to choose 22 successes out of 55 trials. This is 5!2!×(52)!=10\frac{5!}{2! \times (5-2)!} = 10.
  5. Calculate Probability 22 Latin Root: Now, we calculate the probability of getting exactly 22 words with a Latin root. Using the binomial formula: P(X=2)=(52)×(0.492)×(0.513)P(X=2) = \binom{5}{2} \times (0.49^2) \times (0.51^3).
  6. Calculate Probability 22 Latin Root: Now, we calculate the probability of getting exactly 22 words with a Latin root. Using the binomial formula: P(X=2)=(52)×(0.492)×(0.513)P(X=2) = \binom{5}{2} \times (0.49^2) \times (0.51^3). Plugging in the numbers: P(X=2)=10×(0.492)×(0.513)P(X=2) = 10 \times (0.49^2) \times (0.51^3). Let's do the math: P(X=2)=10×(0.2401)×(0.132651)P(X=2) = 10 \times (0.2401) \times (0.132651).

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