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

Three persons work independently on a problem. If the respective probabilities that they will solve it are $\frac{1}{3}$,$\frac{1}{4}$,and $\frac{1}{5}$,then the probability that none can solve it is:

$4$ coins are tossed once. Find the probability of $4$ tails.

$A$ basket contains $5$ apples and $7$ oranges,and another basket contains $4$ apples and $8$ oranges. One fruit is picked out from each basket. Find the probability that the fruits are both apples or both oranges.

In a single throw of $2$ dice,find the probability of getting a total of $8.$

$A$ bag contains $7$ black and $5$ white balls. $A$ ball is drawn out and replaced in the bag. Then a ball is drawn again. What is the probability that both balls were black?