Login/Sign Up
Home » Suppose that two cards are drawn at random from a deck of cards. Let be the number of aces obtained. Then the value of is A. B. C. D.
Suppose that two cards are drawn at random from a deck of cards. Let X be the number of aces obtained. Then the value of E(X) is A. 37 / 221 B. 5 / 13 C. 1 / 13 D. 2 / 13
CBSE | Class 10 | Guides | Maths | NCERT | Probability
Suppose that two cards are drawn at random from a deck of cards. Let X be the number of aces obtained. Then the value of E(X) is A. 37 / 221 B. 5 / 13 C. 1 / 13 D. 2 / 13

Solution:

D. 2 / 13

REASON:

A deck of cards is given.

Let X be the total number of aces you’ve gotten.

Therefore Expectation of \mathrm{X} \mathrm{E}(\mathrm{X})

\mathrm{E}(\mathrm{X})=\sum_{\mathrm{i}=1}^{\mathrm{n}} \mathrm{x}_{\mathrm{i}} \mathrm{p}_{\mathrm{i}}

=0 \times \frac{1128}{1326}+1 \times \frac{192}{1326}+2 \times \frac{6}{1326}

=\frac{204}{1326}

\Rightarrow \mathrm{E}(\mathrm{X})=\frac{2}{13}

As a result, the correct answer is (D).

i

More Material