Question

There are 40 students in a class, out of them 15 are boys. The mean of marks obtained by boys is 33 and that for girls is 35. Find out the mean of marks of all students in the class

Answer 1

Answer : 34.25

Solution :
__________

Given that : Total students = 40

If 15 are boys then girls are = 40–15 = 25

Also given that : Mean of marks of boys = 33

As we know that :

$mean \: = \frac{sum \: of \: observation}{no \: of \: observation}$

According to the question :

$sum \: of \: observation \: = 15 \times 33 = 495$

And also given that : mean of marks obtained by girls = 35

$sum \: of \: observations = 25 \times 35 = 875$
$mean \: = \frac{1370}{40} = 34.25$


Now, total marks = 495+875 = 1370

So, total mean of total marks obtained by all the students :

$mean \: = \frac{1370}{40} = 34.25$

So, total mean will be 34.24