Question

If the average weights of boys and girls of a class are 30 and 32 kg respectively, and the average weight of the whole class is 31.2 kg, then the percentage of girls in the class is

Answer 1

Answer:

percent of girls=60%

Step-by-step explanation:

let no of boys=b and girls=g

then total wt of class=30b+32g

avg wt of class=30b+32g/b+g=31.2

30b+32g=31.2b+31.2 g

32g-31.2g=31.2b-30b

0.8g=1.2b

g/b=1.2/.8=3/2

So b/g=2/3

b/g+1=2/3+1

b+g/g=5/3

g/b+g=3/5

g% =3/5*100=60%

So percent of girls=60%