If the probabilities for A to fail in an examination is 0.2 and that f

1.	If the probabilities for A to fail in an examination is 0.2 and that for B is 0.3, then the probability that either A or B fails is A. > . 5 B. .5 C. ≤ .5 D. 0
Answer» Let E₁ be the event that A fails in an examination and E₂ be the event that B fails in an examination Then, we have P (E₁) = 0.2 and P (E₂) = 0.3 Now, we have to find the P (either E₁ or E₂ fails) ∴ P(either E₁ or E₂ fails) = P(E₁) + P(E₂) – P(E₁⋂ E₂) ≤ P(E₁) + P(E₂) ≤ 0.2 + 0.3 ≤ 0.5 Hence, the correct option is (C)

If the probabilities for A to fail in an examination is 0.2 and that for B is 0.3, then the probability that either A or B fails is A. > . 5 B. .5 C. ≤ .5 D. 0

Answer»

Let E₁ be the event that A fails in an examination

and E₂ be the event that B fails in an examination

Then, we have

P (E₁) = 0.2 and P (E₂) = 0.3

Now, we have to find the P (either E₁ or E₂ fails)

∴ P(either E₁ or E₂ fails) = P(E₁) + P(E₂) – P(E₁⋂ E₂)

≤ P(E₁) + P(E₂)

≤ 0.2 + 0.3

≤ 0.5

Hence, the correct option is (C)

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If the probabilities for A to fail in an examination is 0.2 and that for B is 0.3, then the probability that either A or B fails is A. &gt; . 5 B. .5 C. ≤ .5 D. 0

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If the probabilities for A to fail in an examination is 0.2 and that for B is 0.3, then the probability that either A or B fails is A. > . 5 B. .5 C. ≤ .5 D. 0