Math
posted by Jerry on .
100 students were asked whether they are taking psychology or biology. 61 were taking pyschology, 18 were taking both and 12 were taking neither. how many were taking biology?

Make a Venn diagram with two intersecting circles
label "only biology" as x
place 18 in the intersection
place 43 in the "only psychology"
place 12 outside the two circles
x + 18 + 43 + 12 = 100
x = 27
So Biology was taken by 27+18 or 45 students