Answer:

The average marks of total students in class is 24.6 .

Step-by-step explanation:

We are GIVEN that there are 24 BOYS and 16 girls in a class. For a class test the average marks of boys is 25 and that of girls is 24.

Average or mean formula is = SUM of all values ÷ Total number of observation

Average marks of boys = 25  i.e.;

 25 = Total sum of marks of all boys ÷ Total number of boys

 25 = Total sum of marks of all boys ÷ 24

So, Total sum of marks of all boys = 25 * 24 = 600

Similarly, Average marks of girls = 24  i.e.;

 24 = Total sum of marks of all girls ÷ Total number of girls

 24 = Total sum of marks of all girls ÷ 16

So, Total sum of marks of all girls = 16 * 24 = 384

Now, Average marks of total students = Total sum of marks of boys and girls

                                                                   ÷ Total number of students in class

                                                                = (600 + 384) ÷ (24 + 16)

                                                                = 984 ÷ 40 = 24.6

THEREFORE, average marks of total students in that class is 24.6 .