$A$ single letter is selected at random from the word $PROBABILITY$. The probability that the selected letter is a vowel is

$A$ speaks truth in $20 \%$ of the cases and $B$ in $80 \%$ of the cases. Find the probability that their statements about an incident do not match.

When a die is thrown,let event $A$ be getting a number greater than $3$,and let event $B$ be getting a number less than $5$. What is $P(A \cup B)$?

Three students $A$,$B$ and $C$ are running a race. $A$ and $B$ have the same probability of winning and each is twice as likely to win as $C$. Then,the probability that $B$ or $C$ wins is equal to (assuming there are no ties)

The probability that Krishna will be alive in $10$ years is $7/15$ and the probability that Hari will be alive in $10$ years is $7/10$. What is the probability that both will die within the next $10$ years (in $/150$)?

Three coins are tossed once. Find the probability of getting $3$ tails.