$A$ card is selected at random from a well-shuffled pack of $52$ cards. Find the probability that the selected card is a seven.

In a packet containing $400$ screws,$120$ screws are defective. $A$ screw is picked up randomly from the packet. Then,the probability that the screw picked up is non-defective is .........

If $P(A) = 0.6,$ then $P(\bar{A}) = $ .............

At a fete, cards bearing numbers $1$ to $1000$, one number on one card, are put in a box. Each player selects one card at random and that card is not replaced. If the selected card has a perfect square greater than $500$, the player wins a prize. What is the probability that:
$(i)$ the first player wins a prize?
$(ii)$ the second player wins a prize, if the first has won?

There are $1000$ sealed envelopes in a box,$10$ of them contain a cash prize of $Rs. 100$ each,$100$ of them contain a cash prize of $Rs. 50$ each,$200$ of them contain a cash prize of $Rs. 10$ each,and the rest do not contain any cash prize. If they are well shuffled and an envelope is picked out,what is the probability that it contains no cash prize?

Total number of outcomes in the experiment of tossing an unbiased coin twice is ..........