Question

the average score of girls in the class examination in school is 67 and that of boys is 63. If the average score of the whole class is 64.5 then find the percentage of girls and that of boys in the class.

Answer 1

let number of boys =x
avg marks of boys=63
sum of marks of boys =63x

let number of girls =y
avg marks of girls =67
sum of marks of girls=67y

total sum of Marks=63x+67y


Average = 63x+67y/X+Y
according to problem


Average = 63x+67y/X+Y=64.5
63x+67y=64.5x+64.5y
(67-64.5)y=(64.5-63)x
2.5y=1.5x
25/15=x/y
x/y=5/3

percent of boys is( 5/5+3)*100
=500/8
=62.5%

percent of girls is(3/3+5)*100
=300/8
=37.5%


hope this helps

Answer 2

Answer:

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