AFCAT Model Paper 3

Given:
Number of girls = 40% of the total strength
70% of the boys secured more than 60% marks
80% of the remaining passed with less than or equal to 60% marks
Number of failed boys = 9 boys
Calculation:
Let the number of students in the class be ‘x’
No. of boys = (100 - 40)% of x = 60% of x = 0.6x
No. of boys which either passed with a low percentage or failed = (100 - 70)% of 0.6x
⇒ 0.3 × 0.6x = 0.18x
No. of boys that failed = (100 – 80)% of 0.18x
⇒ 20% of 0.18x
But, 9 boys failed in the examination, hence,
⇒ 0.2 × 0.18x = 9
⇒ 0.036x = 9
⇒x=

9

0.036

=250
∴ There are 250 students in the class