logo

Ask Questions, Get Answers

 
X
 Search
Want to ask us a question? Click here
Browse Questions
Ad
Home  >>  CBSE XII  >>  Math  >>  Model Papers
0 votes

Bag I contains 3 black and 2 white balls. Bag II contains 2 black and 4 white balls. A bag and a ball is selected at random. Determine the probability of selecting a black ball.

Can you answer this question?
 
 

1 Answer

0 votes
Toolbox:
  • If A and B are independant events, \(P(A\cap\;B)=P(A)\;P(B)\)
Step 1:
Let $E_1$ be the event of choosing the bag I
Let $E_2$ be the event of choosing the bag II
Let A be the event of drawing a black ball
$\therefore P(E_1)=P(E_2)=\large\frac{1}{2}$
Step 2:
Now $P(\large\frac{A}{E_1})$=P(drawing a black ball from bag I)
$\Rightarrow \large\frac{3}{5}$
$P(\large\frac{A}{E_2})$=P(drawing a black ball from bag II)
$\Rightarrow \large\frac{2}{6}$
$\Rightarrow \large\frac{1}{3}$
Step 3:
$\therefore$ Probability of selecting a black ball is $\large\frac{1}{2}\times \frac{3}{5}+\frac{1}{2}\times \frac{1}{3}$
$\Rightarrow \large\frac{3}{10}+\frac{1}{6}$
$\Rightarrow \large\frac{7}{15}$
answered Nov 7, 2013 by sreemathi.v
 

Related questions

Ask Question
student study plans
x
JEE MAIN, CBSE, NEET Mobile and Tablet App
The ultimate mobile app to help you crack your examinations
Get the Android App
...