In a class, 60% of the students are boys and the rest are girls. If 40% of the boys and 70% of the girls pass in a test and the number of girls who failed is 42, then the number of boys who failed will be:
Show answer & explanation
Correct answer: D
Explanation
The correct answer is option 4 i.e. 126.
Given:
60% of the students are boys and the rest are girls.
If 40% of the boys and 70% of the girls pass in a test
Number of girls who failed is 42
Calculations:
Let the total number of students be 100x
Number of boys = 60% of 100x = 60x
Number of girls = 40% of 100x = 40x
Number of girls failed = 30% of 40x = 12x
⇒ 12x = 42
⇒ x = 3.5
Number of boys failed = 60% of 60x
⇒ 36x = 36 × 3.5
⇒ 126