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This Friday, Patty has a French vocabulary test as well as a Spanish vocabulary test. To prepare, she made a study card for each word, 42%42\% of which are French. Every time she picks a card, she sticks it back in the deck and shuffles again.\newlineIf Patty picks a study card from the deck 55 times during her first study session, what is the probability that exactly 44 cards have a French word?\newlineWrite your answer as a decimal rounded to the nearest thousandth.\newline____\newline

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Q. This Friday, Patty has a French vocabulary test as well as a Spanish vocabulary test. To prepare, she made a study card for each word, 42%42\% of which are French. Every time she picks a card, she sticks it back in the deck and shuffles again.\newlineIf Patty picks a study card from the deck 55 times during her first study session, what is the probability that exactly 44 cards have a French word?\newlineWrite your answer as a decimal rounded to the nearest thousandth.\newline____\newline
  1. Use binomial probability formula: Use the binomial probability formula: P(X=k)=C(n,k)(p)k(1p)(nk)P(X = k) = C(n, k) \cdot (p)^k \cdot (1-p)^{(n-k)}. Here, n=5n = 5, k=4k = 4, and p=0.42p = 0.42.
  2. Calculate C(5,4)C(5, 4): Calculate C(5,4)C(5, 4) using the formula C(n,k)=n!k!(nk)!C(n, k) = \frac{n!}{k!(n - k)!}. C(5,4)=5!4!(54)!=5C(5, 4) = \frac{5!}{4!(5 - 4)!} = 5.
  3. Calculate (0.42)4(0.42)^4: Calculate (0.42)4(0.42)^4. (0.42)4=0.42×0.42×0.42×0.42=0.03093568(0.42)^4 = 0.42 \times 0.42 \times 0.42 \times 0.42 = 0.03093568.
  4. Calculate (10.42)(54)(1 - 0.42)^{(5 - 4)}: Calculate (10.42)(54)(1 - 0.42)^{(5 - 4)}. (10.42)(54)=(0.58)1=0.58(1 - 0.42)^{(5 - 4)} = (0.58)^1 = 0.58.
  5. Multiply values to find probability: Multiply all the values together to find the probability. P(X=4)=5×0.03093568×0.58=0.089718976P(X = 4) = 5 \times 0.03093568 \times 0.58 = 0.089718976.

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