For two events $A$ and $B$,if $P(A \cup B) = \frac{5}{6}$,$P(A) = \frac{1}{6}$,and $P(B) = \frac{2}{3}$,then $A$ and $B$ are:

For independent events $A_1, A_2, \dots, A_n$,$P(A_i) = \frac{1}{i + 1}$ for $i = 1, 2, \dots, n$. Then the probability that none of the events will occur is:

Two players play the following game: $A$ writes $3, 5, 6$ on three different cards; $B$ writes $8, 9, 10$ on three different cards. Both draw randomly two cards from their collections. Then,$A$ computes the product of the two numbers he/she has drawn,and $B$ computes the sum of the two numbers he/she has drawn. The player getting the larger number wins. What is the probability that $A$ wins?

Two dice are thrown together. If the numbers appearing on the two dice are different,then what is the probability that the sum is $6$?

$A$ six-faced unbiased die is thrown twice and the sum of the numbers appearing on the upper face is observed to be $7$. The probability that the number $3$ has appeared at least once is:

If a die is thrown $2$ times,what is the probability of getting $4$ at least once?