In a class the average of boys and girls is 'A'. The ratio of number of boys and number of girls is 4 : 1 and the average of the boys is A -1 . Find the average of girls.
Answer & explanation
Correct answer: option 3
Ratio of Boys : Girls
4 : 1 = 5 ( sum of ratio of boys and girls )
Let the average of girls = x
ATQ,
5A = 4 (A - 1) + 1x
x = 5A - 4A + 4
x = A + 4
So, the average of girls = A + 4