Q37 of 66 Page 15

Three different coins are tossed together. Find the probability of getting (i) exactly two heads (ii) at least two heads (ii) at least two tails.[CBSE 2016]

When three coins are tossed together possible outcomes are


{HHH, HHT, HTT, HTH, TTT, TTH, THH, THT}


(i) Total no of outcomes : 8


Outcomes having at least two heads : 4




(ii) Total no of outcomes : 8


Outcomes having at least two tails : 4



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35

Two different dice are thrown together. Find the probability of:

(i) getting a number greater than 3 on each die


(ii) getting a total of 6 or 7 of the numbers on two dice [CBSE 2016]

 36

a box consists of 100 shirts of which 88 are good, 8 have minor defects and 4 have major defects. Ramesh, a shopkeeper will buy only those shirts which are good but ‘Kewal’ another shopkeeper will not buy shirts with major defects. A shirt is taken out of the box at random. What is the probability that

(i) Ramesh will buy the selected shirt?


(ii) ‘Kewal’ will buy the selected shirt? [CBSE 2016]

 38

A game consists of tossing a one-rupee coin 3 times and noting the outcome each time. Ramesh wins the game if all the tosses give the same result (i.e. three heads or three tails) and loses otherwise. Find the probability of Ramesh losing the game.[CBSE 2017]

 39

A box contains 80 discs, which are numbered from 1 to 80. If one disc is drawn at random from the box, find the probability that it bears a perfect square number.[CBSE 2011]