Question

in a school 60% of the students are boys.75% of the boys passed the class x exams.40% of the passed boys got first division.80% of thr total students passed the exam and 50% of the passed students got first division
students
​

Answer 1

The answer is 20%

Mark me as brilliant

Answer 2

Let consider total number of student = 100

According the question 60% are boys. ( given)

75% boys of class x passed in exam.     ( given)

∴ Total number of boys passed the class x exams = 60 × 75%

                                                                                      =$\frac{75}{100}$ × 60

                                                                                    =$\frac{3}{4}$ × 60

                                                                                     = 3 ×15= 45

Total 45 boys passed in class x exams.

40% of the passed boys got first division.    ( given)

Number of boys got first division = ( 45 × $\frac{40}{100}$ )

                                                       = ( 45 × $\frac{2}{5}$)

                                                       = ( 9× 2) = 18

Hence 18 boys got first division.

Now according the question 80% of the total students passed the exam.

and 50% of the passed students got first division students.

∴ Number of total students who got first division = ( 80 × $\frac{50}{100}$ )

                                                                                 = ( 80 × $\frac{1}{2}$ )= 40

Hence 40 students of the passed students secure first division.

Ans :- Total 45 boys passed in class x exams.  18 boys got first division and 40 students of the passed students secure first division.