I need help with the following percentage question:
In a 400-people population, it has been done examinations to diagnose anemia and intestinal parasitism. The results made it clear that:
- 80% of the people with anemia have also intestinal parasitism;
- 50% of the people with intestinal parasitism have also anemia;
- 220 people have neither anemia nor intestinal parasitism.
Out of the 400 people, what is the percentage of people with anemia?
I know that the answer is 25%, but how do I get at it?