Question

A class consists of 4 boys and 3 girls. The average marks obtained by the boys and girls are 20 and 30 respectively. Find the class average.
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Answer 1

The class average is 24.29.

Given:

Number of boys in the class = 4

Number of girls in the class = 3

Average marks obtained by boys = 20

Average marks obtained by girls = 30

To find:

The class average

Solution:

According to the given data, 4 boys score an average of 20 marks.

The formula for calculation of the average for boys is given by,

Average = Total marks scored by boys / Number of boys

=> Total marks scored by boys = Average x Number of boys = 20 x 4 = 80

3 girls score an average of 30 marks

=> Total marks scored by girls = Average x Number of girls = 30 x 3 = 90

Class average = Marks scored by boys and girls / Number of students

=> Class average = (80 + 90) / (4 + 3) = 170 / 7 = 24.29

Hence, the class average is 24.29.

#SPJ1

Answer 2

The class average is 24.28

GIVEN:-

• boys = 4 and girls = 3
• average marks obtained by the boys = 20
• average marks obtained by the girls = 30

TO FIND:- class average.

SOLUTION:-

As we know,

Average marks obtained by the boys = Total marks scored by boys/ Total number of boys

Let the Total marks scored by boys be a

By putting values in the formula

$20 = \frac{a}{4} \\ a = 20 \times 4 \\ a = 80$

Similarly,

Average marks obtained by the girls = Total marks scored by girls/ Total number of girls

Let the Total marks scored by boys be b

By putting values in the formula

$30 = \frac{b}{3} \\ b = 30 \times 3 \\ b = 90$

Class average = Total marks of boys + Total marks of girls/ Total number of boys + Total number of girls

$= \frac{80 + 90}{4 + 3} \\ = \frac{170}{7} \\ = 24.28$

Hence, the class average is 24.28

#SPJ2