Quantitative - Mathematics - Word Problems:

Probability

MCQ - 146-12913

Question:

A speaks truth in 75% of cases and B in 80% of cases. In what percentage of cases are they likely to contradict each other, narrating the same incident

Correct Answer: B

Explanation:

Let A = Event that A speaks the truth

B = Event that B speaks the truth

Then P(A) = $\frac{75}{100}$ = $\frac{3}{4}$

P(B) = $\frac{80}{100}$ = $\frac{4}{5}$

P(A &minus ;lie) = 1 − $\frac{3}{4}$ = $\frac{1}{4}$

P(B − lie) = 1 − $\frac{4}{5}$ = $\frac{1}{5}$

Now

A and B contradict each other = [A lies and B true] or [B true and B lies]

= P(A).P(B − lie) + P(A − lie).P(B)

[Please note that we are adding at the place of OR]

= ( $\frac{3}{4}$ × $\frac{1}{5}$ ) +( $\frac{1}{4}$ × $\frac{4}{5}$ ) = $\frac{7}{20}$

= ( $\frac{7}{20}$ × 100) % = 35%

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1297 MCQ for effective preparation of the test of Probability of Word Problems section.

Read the MCQ statement: A speaks truth in 75% of cases and B in 80% of cases. In what percentage of cases are they likely to contradict each other, narrating the same incident , keenly and apply the method you have learn through the video lessons for Probability to give the answer. Record your answer and check its correct answer and video explanation for MCQ No. 146-12913.

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Solve the question for MCQ No. and decide which option (A through D/E) is the best choice to answer the MCQ, then click/tap the blue button to view the correct answer and it explanation.

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