Question

103. In a class 40 % students read Mathematics, 25 % Biology and 15 % both Mathematics and
Biology. One student is select at random. The probability that he reads Mathematics if it is known that he reads biology is
(a)2/5
(b)3/5
(c)4/5​

Answer 1

Answer:

correct option is (b) 3/5

Answer 2

Given : In Class XI of a school 40% of the students study Mathematics and 30% study Biology. 10% of the class study both Mathematics and Biology.

 

Solution :  

We have , 40% students study Mathematics .

Probability of students study Mathematics = 40/100 = 0.4

P (M) = 0.4

 

We have , 30% students study Biology .

so, Probability of study Biology = 30/100 = 0.30

P (B) = 0.3

 

We have,10% of students study both mathematics and biology.

Probability of students study both mathematics and biology = 10/100 = 0.1

P(M ∩ B) = 0.1

 

we know that ,

P(X U Y ) = P( X ) + P( Y ) - P( X ∩ Y )

P( M U B ) = P( M ) + P( B ) - P( M ∩ B)

P( M U B ) = 0.4 + 0.3 - 0.1  

P( M U B ) = 0.6

Hence, Probability of students study Mathematics or biology is 0.6.

HOPE THIS ANSWER WILL HELP YOU...

 

Here are some more questions from this chapter :  

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 at least one of them is 0.95. What is the probability of passing both?

https://brainly.in/question/1842385

The  probability that a student will pass the final examination in both English and Hindi is 0.5 and the probability of passing neither is 0.1. If the probability of passing the English examination is 0.75, what is the probability of passing the Hindi examination?