The probability that a student is not a swimmer is $\frac{1}{5}$. What is the probability that out of $5$ students,$4$ are swimmers?

The probability that an event $A$ happens in a trial is $0.4$. If three independent trials are made,then the probability that $A$ happens at least once is

$A$ dice is thrown $10$ times. If getting an even number is considered as a success,then the probability of $4$ successes is:

$A$ box contains $100$ bulbs,out of which $10$ are defective. $A$ sample of $5$ bulbs is drawn. The probability that none is defective is

Find the probability distribution of the number of doublets in three throws of a pair of dice.

An objective type test paper has $5$ questions. Out of these $5$ questions, $3$ questions have four options each $(a, b, c, d)$ with one option being the correct answer. The other $2$ questions have two options each, namely true and false. $A$ candidate randomly ticks the options. Then, the probability that he/she will tick the correct option in at least four questions, is