An unbiased coin is tossed thrice. The probability of receiving two heads is ..........

In a shop, there are $50$ packets of tea out of which $5$ are under-weight. One packet is selected at random from the lot. Find the probability that an under-weight packet is selected.

If $I$ toss a coin $3$ times and get a head each time,should $I$ expect a tail to have a higher chance in the $4^{th}$ toss? Give a reason in support of your answer.

There are $5$ red,$3$ white and $2$ yellow roses in a vase. One rose is selected at random from the vase. Then,the probability that the selected rose is yellow is ..........

$A$ card is drawn at random from a well-shuffled pack of $52$ cards. The probability of that card being a card of a black suit is .............

$I$ toss three coins together. The possible outcomes are no heads,$1$ head,$2$ heads and $3$ heads. So,$I$ say that probability of no heads is $\frac{1}{4}$. What is wrong with this conclusion?