In a class of 50 students, the ratio of boys to girls is 3 : 2. The average weight of girls is 36 kg less than that of boys. If the average weight of the whole class is 54 kg, find the average weight of boys (in kg).

Explanation

​ Information Given: Total students = 50 Ratio of boys : girls = 3 : 2 Average weight of girls = 36 kg less than boys Average weight of whole class = 54 kg Number of boys = 30 Number of girls = 20 Concept/Formula Used: Average = Total weight / Total students Explanation: Let average weight of boys = x Then average weight of girls = x − 36 Total weight of boys = 30x Total weight of girls = 20(x − 36) = 20x − 720 Total weight of class = 30x + 20x − 720 = 50x − 720 Given average = 54 So, 50x − 720 = 54​ 50 ​ 50x − 720 = 2700 50x = 3420 x = 68.4