Question

a class has 40 students 2/5 of the students in the class are girls 1/2 of the boys 3/8 of the girls know how to swim a) what fraction of the student in the class know how to swim. b) how many students do not how to swim​

Answer 1

Answer:

Given-

total number of students= 40

fraction of girls = 2/5

fraction of boys who know how to swim= 1/2

fraction of girls who know how to swim= 3/8

Solution-

total number of girls in the class = 2/5 * 40

                                                      = 16 girls

total number of boys= 40-16

                                  = 24 boys

boys who know swimming= 1/2 * 24

                                            =12 boys

girls who know swimming= 3/8 * 16

                                           = 6 girls

total students who know swimming= 12+6

                                                           =18 students

a) fraction of students who know swimming  = 18/40

                                                                           =9/20

b) fraction of students who don't know swimming= 1- 9/20

                                                                                  = 11/20