There are $4$ envelopes with addresses and $4$ concerning letters. The probability that letter does not go into concerning proper envelope, is
$\frac{{19}}{{24}}$
$\frac{{21}}{{23}}$
$\frac{{23}}{{24}}$
$\frac{1}{{24}}$
Three coins are tossed once. Find the probability of getting no head.
A fair coin is tossed repeatedly. If tail appears on first four tosses then the probability of head appearing on fifth toss equals
A set $S$ contains $7$ elements. A non-empty subset $A$ of $S$ and an element $x$ of $S$ are chosen at random. Then the probability that $x \in A$ is
Seven chits are numbered $1$ to $7$. Three are drawn one by one with replacement. The probability that the least number on any selected chit is $5$, is
A problem in Mathematics is given to three students $A, B, C$ and their respective probability of solving the problem is $\frac{1}{2} , \frac{1}{3} $ and $\frac{1}{4}$. Probability that the problem is solved is