Question

A box contains 19 balls bearing numbers 1,2,3,…., 19. A ball is drawn at random from the box. Find the probability that the number on the ball is
(i) a prime number
(ii) divisible by 3 or 5
(iii) neither divisible by 5 nor by 10
(iv) an even number

Answer 1

Answer:

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prime numbers :

2 , 3 , 5 , 7 , 9 , 11 , 13 , 17 , 19

total outcomes = 9

P ( prime number ) = 9 / 19

divisible by 3 or 5 :

3 , 5 , 6 , 9 , 10 , 12 , 15 , 18

total outcomes = 8

P ( divisible by 3 or 5 ) = 8 / 19

Neither divisible by 5 nor by 10 :

1,2,3,4,6,7,8,9,11,12,13,14,16,17,18,19

total outcomes = 16

P( neither divisible by 5 nor 10 ) = 16 / 19

Even numbers :

2 ,4,6,8,10,12,14,16,18

total outcomes = 9

P ( even number) = 9 / 19

Answer 2

Answer:

$\huge\fcolorbox{black}{pink}{Answer-}$

Box contains :

19 balls numbered 1 - 19

Prime number : 2 ,3,5,7,11,13,17,19

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total numbers = 8 prime numbers

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divisible by 3 or 5 = 3,5,6,9,10,12,15,18

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total numbers = 8

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neither divisible by 5 nor 10 = 2,3,4,6,7,8,9,11,12,13 14,16,17,18,19

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total numbers = 15

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even numbers = 2,4,6,8,10,12,14,16,18

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total even numbers = 9

P( prime no.) = 8 / 19

P(divisible by 3 or 5 )= 8/ 19

P ( neither divisible by 5 or 10) = 15 / 19

P( even number ) = 9 / 19