$A$ coin is tossed two times. Find the probability of getting at most one head.

If $P(A) : P(\bar{A}) = 3 : 4$,then $P(A) =$ .........

$A$ child's game has $8$ triangles of which $3$ are blue and the rest are red,and $10$ squares of which $6$ are blue and the rest are red. One piece is lost at random. Find the probability that it is a
$(i)$ triangle
$(ii)$ square
$(iii)$ square of blue colour
$(iv)$ triangle of red colour

Box $A$ contains $25$ slips of which $19$ are marked $Rs. 1$ and others are marked $Rs. 5$ each. Box $B$ contains $50$ slips of which $45$ are marked $Rs. 1$ each and others are marked $Rs. 13$ each. Slips of both boxes are poured into a third box and reshuffled. $A$ slip is drawn at random. What is the probability that it is marked other than $Rs. 1$?

$A$ letter of English alphabets is chosen at random. Determine the probability that the letter is a consonant.

If $P(A) : P(\bar{A}) = 5 : 3$,then $P(\bar{A}) = $ ........