There are m boys and n girls in Class 62.

According to the condition that the average class score is 74 in June 1 day, the score is (7 1x+76y)/(x+y)=74, and the score is 3x/2.

Judging from the condition of class average score of 84, it is: (8 1m+90n)/(m+n)=84, and it is: m=2n.

According to the conditions, the average score of boys in Class Two is 79, and the score is (71x+81m)/(x+m) = 79, and the score is 4x.

So, n=2x

Therefore, the average score of girls in Class Two = (76y+90n)/(y+n) = 294x/(7x/2) = 84 (points).