A class has 22 boys and 18 girls. During the holidays, of the students in this class went to do community work. At least, how many girls participated in this work?
(A) 1
(B) 2
(C) 4
(D) 6
(E) 8
Problem 600
Official solution
The correct answer is (B).
Of the total number of students in this class, went to do community work, that is, . The minimum number of female students who participated in this work is obtained when the number of male students who participated is maximum, that is, when 22 male students are involved in the work, leaving a minimum of 2 spots for the female students.