Test Index

Probability

Section: Mathematics

© examsnet.com

Question : 28 of 92

Marks: +1, -0

U_1, U_2, U_3

are three urns.

U_1

contains 5 red, 3 white, 2 back balls;

U_2

contains 4 red, 4 white, 2 black balls and

U_3

contains 3 red, 4 white, 3 black balls. If a ball is chosen at random from an urn chosen at random, then the probability of not getting a black ball is

[AP EAPCET 22 May 2025 S1]

$\frac{7}{30}$
$\frac{23}{30}$
$\frac{2}{5}$
$\frac{11}{30}$

Solution:

Given that

U r n U_1

contains 5 red, 3 white, 2 black balls

U r n U_2

contains 4 red, 4 white, 2 black balls

\underset{3}{\text{UrnU}}

contains 3 red, 4 white, 3 black balls

Total number of balls

=30

Non-black balls

=23

Total probability of selecting one

Ur n = \frac{1}{3}

Probability of getting not a black balls from

U_1

or

U_2

and

U_3

.

= \frac{1}{3} \left(\frac{8}{10} + \frac{8}{10} + \frac{7}{10}\right)

\therefore \text{Required probability} = \frac{1}{3} \times \frac{23}{10} = \frac{23}{30}

© examsnet.com

Go to Question:

Prev Question

Next Question