Find the probability that a leap year has $53$ Thursdays.

There are $5$ white,$7$ red,$4$ black,and $2$ blue identical balls in a box. One ball is selected at random from the box. Find the probability that the selected ball is not white.

$A$ 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

$A$ balanced die is thrown once. Find the probability of getting a prime number.

If you toss a coin $6$ times and it comes down heads on each occasion,can you say that the probability of getting a head is $1$? Give reasons.

There are chits numbered $1$ to $20$ in a box. One chit is drawn at random. Find the probability that the number on the chit is a multiple of $5$. (in $/5$)