Multiple choice general knowledge

The probability that an electronic device produced by a company does not function properly is equal to 0.1. If 10 devices are bought, then the probability, to the nearest thousandth, that 7 devices function properly is

  1. 0.057

  2. 0.478

  3. 0.001

  4. 0
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A Correct answer
Explanation

This is a binomial probability problem where success = device functions (p=0.9) and we want exactly 7 successes in 10 trials. Use the formula P(X=k) = C(n,k) * p^k * (1-p)^(n-k). C(10,7) = 120, so P = 120 * (0.9)^7 * (0.1)^3 ≈ 0.0574. The key is recognizing that 'functioning properly' probability is 0.9, not 0.1.

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