Let a biased coin be tossed 5 times. If the probability of getting 4 heads is equal to the probability of getting 5 heads, then the probability of getting atmost two heads is
$\frac{275}{6^{5}}$
$\frac{36}{5^{4}}$
$\frac{181}{5^{5}}$
$\frac{46}{6^{4}}$
$5$ boys and $5$ girls are sitting in a row randomly. The probability that boys and girls sit alternatively is
A drawer contains $5$ brown socks and $4$ blue socks well mixed. A man reaches the drawer and pulls out $2$ socks at random. What is the probability that they match
A box contains $10$ red marbles, $20$ blue marbles and $30$ green marbles. $5$ marbles are drawn from the box, what is the probability that atleast one will be green?
Let $X$ be a set containing $n$ elements. If two subsets $A$ and $B$ of $X$ are picked at random, the probability that $A$ and $B$ have the same number of elements, is
A fair coin is tossed $100$ times. The probability of getting tails an odd number of times is