Question

In a school there are 800 students appearing for public exam. If 200 students answer Math 120 answer Biology and 40 students answer both Math and Biology. How many students answer Math or Biology?

chapter SETS CLASS 11

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Answer 1

Answer:

Sorry I am student of class 5 .

Answer 2

Given;

No. of students appearing for public exam = 800

No. of students who appeared for Maths = 200

No. of students who appeared for Biology = 120

No. of students who appeared for both Maths and Biology = 40

To find:

No. of students who appeared for Maths or Biology.

Solution:

Let $M$ be the no. of students who appeared for Maths.

Let $B$ be the no. of students who appeared for Biology.

then, n(M) = 200, n(B) = 120, n(M∩B) = 40, n(M∪B) = ?

Here, the no. of students who appeared for Maths and no. of students who appeared for Biology is given. Also, the no. of students who appeared for both Maths AND Biology is given. AND signifies intersection. Hence, n(M∩B) = 40.

We are asked to find the no. of students appeared for Maths OR Biology. OR signifies union. Hence, n(M∪B) is the unknown value.

We have the formula,

n(M∪B) = n(M) + n(B) - n(M∩B)

n(M∪B) = $200+120-40=280$

Hence, 280 students appeared for either Maths or Biology.

Out of 800 students who appeared for a public exam, 280 students answered for Maths or Biology.