Three balanced coins are tossed simultaneously. Find the probability of receiving at least two heads.

$A$ bag contains $10$ red,$5$ blue and $7$ green balls. $A$ ball is drawn at random. Find the probability of this ball being a
$(i)$ red ball
$(ii)$ green ball
$(iii)$ not a blue ball

Chits numbered from $1$ to $120$ are put in a box and a chit is drawn randomly from the box. The probability that the chit drawn bears a $3$-digit number is ............

An integer is chosen between $0$ and $100$. What is the probability that it is
$(i)$ divisible by $7?$
$(ii)$ not divisible by $7?$

There are $5$ red,$8$ white,and $4$ green balls in a box. $A$ ball is drawn at random from the box. Find the probability that the ball drawn is not green.

There are boards numbered $1$ to $50$ in a box. One board is selected at random. Find the probability that the number on the board is a multiple of $10$. (in $/10$)