The probability of an impossible event,i.e.,$P(\phi)$,is:

$A$ coin is tossed $3$ times. Find the chance that head and tail show alternately.

One card is drawn from a well-shuffled deck of $52$ cards. Calculate the probability that the card will not be a black card.

An urn contains $10$ green,$12$ yellow,and $11$ white balls. What is the probability that when $2$ balls are selected,both are green?

$1$ bag contains $4$ white and $2$ black balls. Another bag contains $3$ white and $5$ black balls. If $1$ ball is drawn from each bag,find the probability that both balls are black.

What is the probability that a non-leap year has $53$ Wednesdays?