Question

a class consists of 50 students out of which 30 are girls.the mean marks scored by girls in test is 73 out of 100 and that of boys is 71.determine the mean of whole class

Answer 1

Case 1 :
For girls
Mean=total marks /total number of girl
73=total marks /30
Total marks =2190
Case 2 :
For boys
Mean=total marks /total number of boys
71=total marks /20
Total marks =1420
Grand total of the class
=total marks of girls +total marks of boys
=2190+1420
=3610
Mean =3610/50
=72.2