Question

i. There are 40 students in a class 20 take chemistry class and 25 take physics class 8

students take both. How many are there in at least one classes ?and how many students

take none of these classes ​

Answer 1

Answer:

in class 20 there have 2 students and in class 8 there have 3to 4 students

Answer 2

Step-by-step explanation:

Given:-

There are 40 students in a class 20 take chemistry class and 25 take physics class 8

There are 40 students in a class 20 take chemistry class and 25 take physics class 8 students take both.

To find:-

How many are there in at least one classes ?

and how many students take none of these classes

Solution:-

No. of students in a class =40

No. of students who took Chemistry class =

n(C)=20

No. of students who took Physics class=

n(P)=25

No. of students who took both chemistry and physics classes=n(CnP)=8

Using formula :-

we know that

n(AUB)=n(A)+n(B)-n(AnB)

n(CUP)=n(C)+n(P)-n(CnP)

=>nCUP)=20+25-8

=>n(CUP)=45-8

= n(CUP)=37

Total students who took at least one class =37

No.of students who took none of the classes=40-37=3