logo

Ask Questions, Get Answers

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

In an entrance test that is graded on the basis of two examinations,the probability of a randomly chosen student passing the first examination is 0.8 and the probability of passing the second examination is 0.7.The probability of passing atleast one of them is 0.95.What is the probability of passing both?

Can you answer this question?
 
 

1 Answer

0 votes
Toolbox:
  • $P(A\cup B)=P(A)+P(B)-P(A\cap B)$
Step 1:
Given probability of first examination P(I)=0.8
P(II)=0.7
Probability of atleast (I or II)=$P(I \cup II)=0.95$
$\therefore P(I \cup II)=P(I)+P(II)-P(I \cap II)$
$0.95=0.8+0.7-P(I \cap II)$
Step 2:
$\therefore P(I \cap II)=1.5-0.95$
$\Rightarrow 0.55$
$\therefore$ Probability of passing both is 0.55
Hence (A) is the correct answer.
answered Jul 2, 2014 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
...