Question
In a classroom, the ratio of boys to girls is 3:1. The
average marks of all the girls are given as z - 6 , while the overall average marks for all the students in the class are z + 3 . Determine the average marks of all the boys in the class.Solution
Let the number of boys and number of girls in the class be '3a' and 'a', respectively. Total marks of the class = 4a X (z + 3) = 4az + 12a Total marks of all girls = a X (z - 6) = az - 6a So, total marks of all boys = (4az + 12a) - (az - 6a) = (3az + 18a) Therefore, average marks of boys = (3az + 18a) /3a = (z + 6)
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