In a box, there are $20$ cards, out of which $10$ are lebelled as $\mathrm{A}$ and the remaining $10$ are labelled as $B$. Cards are drawn at random, one after the other and with replacement, till a second $A-$card is obtained. The probability that the second $A-$card appears before the third $B-$card is
$\frac{11}{16}$
$\frac{13}{16}$
$\frac{9}{16}$
$\frac{15}{16}$
Out of $40$ consecutive natural numbers, two are chosen at random. Probability that the sum of the numbers is odd, is
In a lottery $50$ tickets are sold in which $14$ are of prize. A man bought $2$ tickets, then the probability that the man win the prize, is
A dice is rolled three times, find the probability of getting a larger number than the previous number each time ?
A bag contains $8$ black and $7$ white balls. Two balls are drawn at random. Then for which the probability is more
In four schools ${B_1},{B_2},{B_3},{B_4}$ the percentage of girls students is $12, 20, 13, 17$ respectively. From a school selected at random, one student is picked up at random and it is found that the student is a girl. The probability that the school selected is ${B_2},$ is