All Exams Test series for 1 year @ ₹349 only
Question

The events A and B are independent among three events A, B and D. If \(P(A\cap B\cap D) = 0.04\), \(P(D\mid A\cap B) = 0.25\) and \(P(B) = 4P(A)\), then what is the value of \(P(A\cup B)\)?

This question was previously asked in
NDA 2 2026 GAT Question Paper (13-Sep-2026)
The correct answer is

0.84

Since \(P(D\mid A\cap B)=\dfrac{P(A\cap B\cap D)}{P(A\cap B)}\), we get \(P(A\cap B) = \dfrac{0.04}{0.25} = 0.16\). As A and B are independent, \(P(A)P(B) = 0.16\), and with \(P(B)=4P(A)\) this gives \(4P(A)^2 = 0.16\), so \(P(A)=0.2\) and \(P(B)=0.8\). Hence \(P(A\cup B) = P(A)+P(B)-P(A\cap B) = 0.2+0.8-0.16 = 0.84\).

Was this answer helpful?

Similar Questions

  1. A student appears for tests I, II and III. The student is considered successful if the passes in tests I, II or I, III or all the three. The probabilities of the student passing in test I, II and III are m, n and 1/2 respectively. If the probability of the student to be successful is 1/2, then which one of the following is correct?

  2. If \(\rm P(A\cup B)=\dfrac{5}{6}, P(A\cap B)=\dfrac{1}{3}\:and\:P(\bar A)=\dfrac{1}{2}\) , then which of the following is/are correct?

    1. A and B are independent events.

    2. A and B are mutually exclusive events.

    Select the correct answer using the code given below.

  3. In a lottery of 10 tickets numbered 1 to 10, two tickets are drawn simultaneously. What is the probability that both the tickets drawn have prime numbers?

  4. In a series of 3 one-day cricket matches between teams A and B of a college, the probability of team A winning or drawing are 1/3 and 1/6 respectively. If a win, loss or draw gives 2, 0 and 1 point respectively, then what is the probability that team A will score 5 points in the series?

  5. A question is given to three students A, B and C whose chances of solving it are \(\frac{1}{2},\frac{1}{3}\) and \(\frac{1}{4}\)  respectively. What is the probability that the question will be solved?


Important Questions from Multiplication Theorem of Events

  1. The probability that A speaks truth is 4 /  5 while this probability for B is 3 / 4. The probability that they contradict each other when asked to speak on a fact is

  2. For any two events A and B, the probability that at least one of them occur is 0.6. If A and B occur simultaneously with a probability 0.3, then P(A') + P(B') is

  3. A student appears for tests I, II and III. The student is considered successful if the passes in tests I, II or I, III or all the three. The probabilities of the student passing in test I, II and III are m, n and 1/2 respectively. If the probability of the student to be successful is 1/2, then which one of the following is correct?

  4. If \(\rm P(A\cup B)=\dfrac{5}{6}, P(A\cap B)=\dfrac{1}{3}\:and\:P(\bar A)=\dfrac{1}{2}\) , then which of the following is/are correct?

    1. A and B are independent events.

    2. A and B are mutually exclusive events.

    Select the correct answer using the code given below.

  5. In a lottery of 10 tickets numbered 1 to 10, two tickets are drawn simultaneously. What is the probability that both the tickets drawn have prime numbers?

Need Expert Advice?
Test Series
NDA img
Defence
NDA 2026 Mock Test Series (Latest Pattern)
503 Tests 1 Tests Free
1066 Attempts
4.6(137)
English, Hindi

Start Your Preparation with Prepp Mobile App

Download the app from Google Play & App Store
Download the app from Google Play & App Store
Prepp Mobile App