There are 10 boys and 20 girls in a class. In a class test, the mean score of the boys is 77. The mean score of the girls is 80. What is the mean score of the whole class?

To calculate the mean of the whole class:1) Find the sum of the individual scores of the whole class. Boys: 10 x 77 = 770Girls: 20 x 80 = 1600Total of Boys and Girls: 770 + 1600 = 23702) Divide the sum of the individual scores by the total number of students in the class.Sum of individual scores = 2370Total number of students: 10 + 20 = 302370/30 = 79The mean of the whole class is 79.