The Total solution for NCERT class 6-12
A lot consists of144 ball pens of which 20 are defective and the others are good. Nuri will buya pen if it is good, but will not buy if it is defective.
Answer - 21 : -
The shopkeeper draws one pen at random and gives it to her. What is the probability that
(i) She will buy it?
(ii) She will not buy it?
Answer - 22 : -
A game consists oftossing a one rupee coin 3 times and noting its outcome each time.
Answer - 23 : - 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.
The total number of outcomes = 8 (HHH, HHT,HTH, THH, TTH, HTT, THT, TTT)
Total outcomes in which Hanif will lose thegame = 6 (HHT, HTH, THH, TTH, HTT, THT)
P (losing the game) = 6/8 = ¾ = 0.75
A die is throwntwice. What is the probability that
Answer - 24 : -
(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]
Answer - 25 : -
(i) If two coins aretossed simultaneously there are three possible outcomes—two heads, two tails orone of each. Therefore, for each of these outcomes, the probability is 1/3
(ii) If a die isthrown, there are two possible outcomes—an odd number or an even number.Therefore, the probability of getting an odd number is 1/2