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For the next three (03) items that follow :
Let A, B, C and D be mutually exclusive and exhaustive events and $\frac{P(A)}{2} = \frac{P(B)}{3} = \frac{P(C)}{5} = \frac{P(D)}{8}$.

What is \(\frac{[2P(A) + 3P(B)]}{[4P(C) + 5P(D)]}\) equal to ?

This question was previously asked in
NDA 1 2026 GAT Question Paper (12-Apr-2026)
The correct answer is
13/60

To solve the problem, we are given that the events \(A\), \(B\), \(C\), and \(D\) are mutually exclusive and exhaustive. Furthermore, it is given that:

\(\frac{P(A)}{2} = \frac{P(B)}{3} = \frac{P(C)}{5} = \frac{P(D)}{8} = k\)

Here, \(k\) is a constant. From this equation, we can express the probabilities of each event as:

  • \(P(A) = 2k\)
  • \(P(B) = 3k\)
  • \(P(C) = 5k\)
  • \(P(D) = 8k\)

Since the events are exhaustive, their probabilities sum to 1:

\(P(A) + P(B) + P(C) + P(D) = 1\)

Substituting the expressions for the probabilities, we have:

\(2k + 3k + 5k + 8k = 1\)

Simplifying this gives:

\(18k = 1\)

Therefore, \(k = \frac{1}{18}\).

Next, we need to find the value of:

\(\frac{[2P(A) + 3P(B)]}{[4P(C) + 5P(D)]}\)

Substituting the values of the probabilities:

\(\text{Numerator} = 2(2k) + 3(3k) = 4k + 9k = 13k\)

\(\text{Denominator} = 4(5k) + 5(8k) = 20k + 40k = 60k\)

Thus, the expression simplifies to:

\(\frac{13k}{60k} = \frac{13}{60}\)

The correct answer is therefore \(\frac{13}{60}\).

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