Question:
In a class, 60% of the students are girls and the rest are boys. There are 30 more girls than boys. If 68% of the students, including 30 boys, pass an examination, the percentage of the girls who do not pass is
Correct Answer: 20
Let number of girls and boys be 3x and 2x respectively.
Given,
3x-2x=30
Or x = 30. So the number of students = 3x+2x=5x =150.
Also, number of girls (3x) and boys (2x) = 90 and 60 respectively.
Number of students pass the exam = 68% of 150=102.
Number of girls pass the exam = 102-30 = 72 .
Therefore, number of girls who fail in the exam = 90-72=18
Hence, percentage of girls fail the exam = $\frac{18}{90}\times 100=20%$
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