In this problem, we find out that the ratio is 3:7. So this ratio is essentially telling us (girls avg score):(boys avg score)
So, if we find out the ratio (no. of girls):(no. of boys), shouldn’t it be 7:3 and so, minimum no. of girls = 7?
why is the ratio of scores a direct indicator of the no. of girls?
I don’t get the question - there are more boys than girls?
thats what @gregmat said but i dont get it 
What exactly do you not get?
I don’t understand how no. of boys is greater…? And also, how the ratio 3:7 which I assume indicates the ratio of avg scores of girls : boys is directly proportional to the no. of girls : boys (shouldn’t it be 7:3)
This is the “mixture” trick.
Because the combined average is closer to the boys score, that means there must be more boys in the class.
