Question

A bag contains 3 red balls, 5 blue balls and 7 black balls. If a ball is drawn at random find the probability of getting not blue *


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Answer 1

Answer:

2/3

Explanation:

P(b') =1-P(b)

=1-5/15

=10/15

=2/3

Answer 2

Question

A bag contains 3 red balls, 5 blue balls and 7 black balls. If a ball is drawn at random find the probability of getting not blue *

To find

the probability of not getting a blue ball

solution

Number of red balls = 3

Number of blue balls = 5

Number of black balls = 7

Total number of balls in the bag = 3+5+7

Total number of balls in the bag = 15

${ \underline {\boxed{ \sf{ probability=\frac{ No.of \: favourable \: outcome }{Total \: number \: of \: favourable \: outcome} }}}}$

OR

${ \underline{ \boxed{\sf \color{red}{P(A) = n(A)/ n(S)}}}}$

Where,

• P(A) is the probability of an event “A”.
• n(A) is the number of favourable outcomes.
• n(S) is the total number of events in the sample space

*Note: Here, the favourable outcome means the outcome of interest.

Now,

The probability of getting a blue ball = 5/15

the probability of getting a blue ball= 1/3

$\boxed{ \sf \color{grey}{The \: probability \: that \: an \: event \: doesn't \: occur \: = 1- p(A)}}$

so,

The probability of not getting a blue ball = 1- 1/3

the probability of not getting a blue ball= 3- 1/3

the probability of not getting a blue ball= 2/3

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