Bismuth has a half-life period of $5 \text{ days}$. $A$ sample originally has a mass of $1000 \text{ mg}$. What is the mass of Bismuth remaining after $30 \text{ days}$ (in $.625$)?

India and Pakistan play a $5$-test hockey series. What is the probability that India wins at least three games?

If the sum of mean and variance of a binomial distribution for $5$ trials is $1.8$,then the probability of success is:

$A$ fair coin is tossed $n$ times such that the probability of getting at least one head is at least $0.9$. Then the minimum value of $n$ is:

Two dice are thrown $5$ times,and each time the sum of the numbers obtained being $5$ is considered a success. If the probability of having at least $4$ successes is $\frac{k}{3^{11}}$,then $k$ is equal to

If $X$ is a binomial variate with mean $6$ and variance $2$,then the value of $P(5 \leq X \leq 7)$ is