In a class, 60% of the students are girls and the rest are boys, 45% of the girls pass an examination and 40% of the boys failed. If the number of girls who failed in 66, the number of boys passed the examniation is:
Show answer & explanation
Correct answer: B
Explanation
The correct answer is option 2 i.e. 48
Let the total number of students be 100a
⇒ Number of girls = 60x
⇒ Number of boys = 40x
Number of girls failed = (100 - 45)% × 60x = 55/100 × 60x
⇒ 33x
According to the question;
⇒ 33x = 66
⇒ x = 2
⇒ 100x = 200
Percentage of boys who passed the exam = (100 - 40)% × 40x
⇒ 24x
⇒24x = 24 × 2 = 48