Q9 of 98 Page 705

A box contains 90 discs, numbered from 1 to 90. If one disc is drawn at random from the box, the probability that it bears prime number less than 23 is

Total numbers of elementary events are: 90


Let E be the event of getting a prime number less than 23


Favourable numbers are: 2, 3, 5, 7, 11, 13, 17, 19


Numbers of favourable outcomes = 8


P (E) = 8/90 = 4/45


4/45

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