posted by josh .
From a survey of 100 college students, a marketing research company found that 50 students owned iPods, 50 owned cars, and 20 owned both cars and iPods.
50-20 = 30 owned only cars
50-20 = 30 owned only iPods
That leaves 20 outside the diagram boundaries, owning neither iPod nor car
30 car only
30 iPod only
20 both, intersection of circles
20 outside, own neither