Question

a box contains cards numbered 3,5,7,9...,35,37. A card is drawn at random from the box. Find the probability that the numbe on the drawn card is a prime number

Answer 1

Hi ,

We know that ,
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The probability event E

P( E ) = Number of outcomes favourable to E / Number of all

possible outcomes of the experiment
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According to the problem given ,

Number of all possible outcomes =

Number of cards the box contains = 18 -------( 1 )

( 3,5,7,9,11,13,15,17,19,21,23,25,,27,29,31,33,35,37 )

Number of outcomes favourable = 11 ----- ( 2 )

( since prime number cards in the box are

3 , 5 ,7, 11 , 13 ,17 , 19 ,23 , 29 , 31 , 37 )

P( E ) = ( 1 ) / ( 2 )

= 11 / 18

= 0.61111..

= 0.61 ( approx )

I hope this helps you.

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Answer 2

Number of favourable outcomes=18

P(of getting a prime number)=11/18=0.66approx