in a class of 30 students 22 study physics 19 study chemistry 6 study neither chemistry nor physics. find the number of stduents who study both subjects

Question

 its about set and notation book answer is 17

Answer 1

Let X be the number of students taking both chem and physics.

 

THen the number of students taking chemistry is 19 - x

and the number of students taking physics is 22-x

 

THe total numnber is 30.

So (19-x)+(22-x)+x + 6 = 30

     47 - x = 30

 

    47 - x- 47 = 30-47

     -x = -17

    x= 17

 

5 take physics only.

2 take chemistry only

17 students take both.

6 take neither.