In a class 20 pupils like science, 13 pupils like history,8 pupils like both subjects and 9 pupilz do no not like either subject..use a Venn diagram to find how many pupils were in the class.....?? Help me

3 answers

so, did you draw and label the Venn diagram yet? It should be clear that the number of students is

20+13-8+9
Make a rectangle and draw two overlapping circles.
in the intersection put the 8

subtract 8 from the 20 and put 12 in one of the pieces of the circle.

Then subtract 8 from 13 and place 5 in the other open part of the circle

Put the 9 in the rectangle, but not in the circle.

add 9, 8, 12, 5 to get the number of students.
Always remember when there is an overlap, you have to subtract that overlap from the other numbers.