Question

The ratio of number of boys and girls in a class is 3 : 2. In the 1st semester exam 20% of boys and 25% of girls get more than or equal to 90% marks. What percentage of students get less than 90% marks ?

Answer 1

Let the no. of boys be 3x and girls be 2x
No. of boys scoring more than 90%
= 20% of 3x
= 20/100 ×3x
= 3x/5
No. of boys getting less than 90= 3x-3x/5
= 12x/ 5
No. of girls getting above 90= 25% of 2x
= 25/ 100 × 2x
= x/2
No. of girls getting less than 90= 2x - x/2
= 3x/ 2
Percentage of student getting less than 90
= (12x/ 5 + x/2) × 100 / (3x+ 2x)%
= 290x / 5x %
= 58%