In a class of students (Boys and Girls), there are 60% girls.  The average of the boys is 58 Kg and that of the girls is 52 Kg.  What is the average of the whole class is?

54.4

                                 Boys         Girls

No. of students →        2      :      3

Average            →       58            52   

Total Weight     →      116          156

Average weight of the class = \(\frac{116\;+\;156}{5}\) = 54.4