Practicing Success

Target Exam

CUET

Subject

-- Mathematics - Section B1

Chapter

Probability

Question:

The probability of drawing a diamond card in each of the two consecutive draws from a well shuffled pack of cards, if the card drawn is not replaced after the first draw, is

Options:

$\frac{4}{17}$

$\frac{13}{17}$

$\frac{1}{17}$

none of these

Correct Answer:

$\frac{1}{17}$

Explanation:

Let A be the event of drawing a diamond card in the first draw and B be the event of drawing a diamond card in the second draw. Then,

$P(A)=\frac{^{13}C_1}{^{52}C_1}=\frac{13}{52}=\frac{1}{4}$

After drawing a diamond card in first draw 51 cards are left out of which 12 cards are diamond cards.

∴ P(B/A) = Probability of drawing a diamond card in second draw when a diamond card has already been drawn in first draw

$P(B/A)=\frac{^{12}C_1}{^{51}C_1}=\frac{12}{52}=\frac{4}{17}$

Hence,

Required probability = $P( A ∩ B)$

⇒ Required probability = $P(A) P(B/A)$

⇒ Required probability = $\frac{1}{4}×\frac{4}{17}=\frac{1}{17}$