Two cards are drawn at random and without replacement from a pack of $52$ playing cards. Finds the probability that both the cards are black.
There are $26$ black cards in a deck of $52$ cards.
Let $P(A)$ be the probability of getting a black card in the first draw.
$\therefore $ $P(A)=\frac{26}{52}=\frac{1}{2}$
Let $\mathrm{P}(\mathrm{B})$ be the probability of getting a black card on second draw. since the card is not replaced,
$\therefore $ $P(B)=\frac{25}{51}$
Thus, probability of getting both the cards black $=\frac{1}{2} \times \frac{25}{51}=\frac{25}{102}$
If $P(A) = 2/3$, $P(B) = 1/2$ and ${\rm{ }}P(A \cup B) = 5/6$ then events $A$ and $B$ are
The odds against a certain event is $5 : 2$ and the odds in favour of another event is $6 : 5$. If both the events are independent, then the probability that at least one of the events will happen is
The probability that a man will be alive in $20$ years is $\frac{3}{5}$ and the probability that his wife will be alive in $20$ years is $\frac{2}{3}$. Then the probability that at least one will be alive in $20$ years, is
A card is drawn from a pack of $52$ cards. A gambler bets that it is a spade or an ace. What are the odds against his winning this bet
If odds against solving a question by three students are $2 : 1 , 5:2$ and $5:3$ respectively, then probability that the question is solved only by one student is