A lot consists of 144 ball pens of which 20 are defective, and the others are good. Nuri will buy a pen if it is good, but will not buy if it is defective. The shopkeeper draws one pen at random and gives it to her. What is the probability that

(i) She will but it?

(ii) She will not buy it?

A die is thrown twice. What is the probability that

(i) 5 will not come up either time?

(ii) 5 will come up at least once?

[Hint: Throwing a die twice and throwing two dice simultaneously are treated as the same experiment]

A game consists of tossing a one rupee coin 3 times and noting its outcome each time. Hanif wins if all the tosses give the same result, i.e., three heads or three tails, and loses otherwise. Calculate the probability that Hanif will lose the game.

in a game of musical chairs, the person playing music has been advised to stop playing the music at any time within 1 minute after she starts playing. What is the probability that the music will stop within the first 20 seconds after starting?

A dart is thrown at a circular board which has regions marked for scoring. If the dart hits the region 1, the player gets 50 points and if it hits the region 2, the player gets 100 points. If the dart hits the board, find probability of the player getting 100 points.