Two cards are drawn from a pack of $52$ cards. What is the probability that one of them is a queen and the other is an ace
$\frac{2}{{663}}$
$\frac{2}{{13}}$
$\frac{4}{{663}}$
None of these
In a college, $25\%$ of the boys and $10\%$ of the girls offer Mathematics. The girls constitute $60\%$ of the total number of students. If a student is selected at random and is found to be studying Mathematics, the probability that the student is a girl, is
A die is thrown. Describe the following events : $A$ : a number less than $7.$ Find the $A \cup B$.
A bag $x$ contains $3$ white balls and $2$ black balls and another bag $y$ contains $2$ white balls and $4$ black balls. A bag and a ball out of it are picked at random. The probability that the ball is white, is
Three dice are thrown simultaneously. What is the probability of obtaining a total of $17$ or $18$
A box contains $3$ white and $2$ red balls. A ball is drawn and another ball is drawn without replacing first ball, then the probability of second ball to be red is