Two coins are tossed. Find the probability that two heads are obtained.

From a book containing $100$ pages,one page is selected randomly. The probability that the sum of the digits of the page number of the selected page is $11$,is

The probability of an event $A$ happening in one trial is $0.4$. The probability that the event $A$ happens at least once in three independent trials 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?

$A$ die is rolled,find the probability that an even number is obtained.

$A$ mapping is selected at random from the set of all the mappings of the set $A = \{1, 2, ..., n\}$ into itself. The probability that the mapping selected is an injection is