Question 304705
a class has 24 boys and 16 girls. On a test the class mean was 75. the mean of the girl's score was 72. What was the mean of the boy's sccores?

24+16 = 40 students....  mean = 75  
Total scored by 40 students = 3000

Girls = 16 ....their mean = 72 
total scored by girls = 16*72= 1152

Difference between the scores will give total score of boys.

3000-1152 = 1848

Number of boys = 24 

their mean will be 1848 / 24

=77