Total Members Sometimes there are members that do not belong to either set A or B.In that case the total number of members=Size A+Size B-Number of common members+Number of members not in A or B.# M- ~, S$ u( H" x, n: P2 f
Example:
3 {% d& T. n" Y1 O& I7 ]' A1 | In an office, 35 people drink coffee, 27 drink tea, 12 drink both, and 4 drink neither. The total number of people in the office = 35+27-12+4=54.1 x; k9 j m: N) Q1 S
In a class of 40 students, 20 study algebra, 15 study geometry, 8 study both.The total number of students that do not study either=40-(20+15-8)=13 |
发表于 2012-8-15 12:55:17
