Question

number of student in a class is 75 out of which 33 1 /3% are boys and rest are girls the average score in mathematics of boys is 66 2/3% more than that of the girls if the average score of all the student is 66 then the average score of the girls is

Answer 1

Answer:

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