The probability of getting head and tail alternately in three throws of a coin (or a throw of three coins) is:

$A$ 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:

The probabilities of two persons to hit a target are $\frac{1}{4}$ and $\frac{1}{5}$ respectively. The probability that the target is being hit when both of them attempt independently is

$A$ letter is chosen at random from the word $ASSASSINATION$. Find the probability that the letter is a vowel. (in $/13$)

If a point $A(x, y)$ lies in the region bounded by the $y$-axis,straight lines $2y+x=6$ and $5x-6y=30$,then the probability that $y < 1$ is