In a carton of $20$ bulbs,$4$ bulbs are defective. Find the probability that a bulb selected at random is non-defective.

One number is selected at random from one-digit natural numbers. The probability of that number being even is $\ldots \ldots \ldots$

$A$ triangular target with sides measuring $5 \, cm, 12 \, cm$,and $13 \, cm$ is drawn on a square board with side $20 \, cm$. Find the probability that a dart hitting the board hits the target.

There are $40$ students in Class $X$ of a school,of whom $25$ are girls and $15$ are boys. The class teacher has to select one student as a class representative. She writes the name of each student on a separate card,the cards being identical. Then she puts cards in a bag and stirs them thoroughly. She then draws one card from the bag. What is the probability that the name written on the card is the name of $(i)$ a girl? $(ii)$ a boy?

$A$ carton consists of $100$ shirts of which $88$ are good,$8$ have minor defects and $4$ have major defects. Jimmy,a trader,will only accept the shirts which are good,but Sujatha,another trader,will only reject the shirts which have major defects. One shirt is drawn at random from the carton. What is the probability that
$(i)$ it is acceptable to Jimmy? $\quad (ii)$ it is acceptable to Sujatha?

Two balanced dice are rolled. Find the probability that the sum of numbers on two dice is smaller than $7$.