Question

The radio of boys and girls in a class is 5 : 3 , 20% of the boys and 60% of the girls have passed in first class . what percentage of the class has passed in first class ?

Answer 1

Let the no. of boys is $5x$

and no. of girls $=3x$

and total no. of student in class $5x+3x=8x$

no. of boys who passed in first class $=5x\times \frac{20}{100}=x$

no. of girls who passed in first class $=3x\times \frac{60}{100}=1.8x$

total no. of students who have passed $=x+1.8x=2.8x$

percentage of the class has passed $=\frac{2.8x}{8x}\times 100$

$=35$%