Question

The average score of boys in an examination in a school is 81 and that of the girls is 83 and the average score of the school is 81.8. Then what will be ratio between the number of girls to the number of boys, in the examination?
A) 3:2
B) 2:3
C) 4:3
D) 3:4

Answer 1

Q:

The average score of boys in an examination in a school is 81 and that of the girls is 83 and the average score of the school is 81.8. Then what will be ratio between the number of girls to the number of boys, in the examination?

A) 3:2
B) 2:3
C) 4:3
D) 3:4

Answer:   B) 2:3 

Explanation:

Let the number of boys = b
Let the number of girls = g
From the given data,
 
81b + 83g = 81.8(b + g)
81.8b - 81b = 83g - 81.8g
0.8b = 1.2g
b/g = 1.2/0.8 = 12/8 = 3/2
=> g : b = 2 : 3
 
Hence, ratio between the number of girls to the number of boys = 2 : 3.