determine the people who are affected?

Question

In a group of 40 people ,10 are healthy and every person of the remaining 30 has either high blood pressure, high level of cholesterol or both. If 15 have high blood pressure and 25 have high level of cholesterol.How many people have high blood pressure and a high level of cholesterol?

Answer 1

VENN DIAGRAM:

 

Draw 2 overlapping circles.  One is labelled bp for blood pressure, one is labelled c for cholesterol.

 

Let x represent the overlap area for people who have both high blood pressure and high cholesterol.

 

Since 15 total have high blood pressure, the area for only high bp is "15-x"

 

Since 25 total have high cholesterol, the area for only high cholesterol is "25-x"

 

x = both high bp and c

15-x = high bp only

25-x = high c only

 

(15-x) + x + (25-x) = 30

40 - x = 30

 x = 10

 

10 people have both high blood pressure and high cholesterol

5 people have high bp but not high cholesterol

15 people have high cholesterol but not high bp