Question

(9.) There are two boxes containing 5 white and 6 blue balls and 3 white and 7 blue
respectively. If one of the the boxes is selected at random and a ball is drawn from
the probability that the ball is blue is
(a) 115/227
(b) 83/250 5676
(c) 137/220
(d) 127/25o​

Answer 1

Solution:

Given:

• 1st box contains 5 white balls and 6 blue balls.
• 2nd box contains 3 white balls and 7 blue balls.

To find:

• Probability of getting blue ball.

We know that,

$\implies \sf Probability = \dfrac{Favourable\;outcome}{Total\;outcome}$

Case 1: Box 1st

⇒ No. of white balls = 5

⇒ No. of blue balls = 6

Case 2: Box 2nd

⇒ No. of white balls = 3

⇒ No. of blue balls = 7

Now, Total No. of white balls = 8

And, Total No. of blue balls = 13

And Total balls in both boxes = 21

$\sf Now,\;probability\;of\;getting\;blue\;balls=\dfrac{Total\;No.\;blue\;balls}{Total\;No.\;of\;balls}\\ \\ \\ \implies Probability\;of\;getting\;blue\;balls = \dfrac{13}{21}$

Hence, Probability of getting blue balls = 13/21.

Answer 2

Answer :

Probability of getting blue ball = 13/21

Solution :

Balls in box no 1 = 5 white and 6 blue

Balls in box no 2 = 3 white and 7 blue

We have to find the probability of getting blue ball.

Probability of an event = Favourable Outcomes/ Total no of outcomes

Here, there are total 13 blue balls, so favourable outcomes = 13

And there are total 21 balls in both the boxes, so total number of outcomes = 21

=> Probability of getting blue ball = 13/21

Hence, none of the given options is correct.