Question

The average of marks scored by the students of a class is 68.the average of the marks of the girls in the class is 80 and that of boys is 60.what is the percentage of boys in the class?

Answer 1

let no of girls be x...no of boys be y....then 80x+60y/x+y=68...So x/y=2/3..%=3×100/5=60%

Answer 2

Answer:

The percentage of boys in the class is 60%.

Step-by-step explanation:

The total marks scored by the students=68

Average marks of girls=80

Average marks of boys=60

To find the percentage of boys

So we have  

gx 80 +b x 60=(g+b)(68)

Simplify the above eqn

80g+60b=68g+68b

80g-68g=68b-60b

By shifting the like terms we get

12g=8b

Divide by 4

3g=2b

So g=2 and b=3

To find the total percentage of boys

3/5x 100

Multiply 3 x 100=300

Then divide 300 by 5 we get

=60%

Therefore the total percentage of the boys in a class is 60%