Some students in Class 1 and Class 2 participated in a certain mathematics competition. The average score of boys in Class 1 was 71 points, the average score of girls was 76 points, and the average score of the whole class was 74 points; the average score of boys in Class 2 was 71 points. The score is 81 points, the average score of girls is 90 points, the average score of the whole class is 84 points, and the average score of all the boys in the two classes is 79 points, what is the average score of all the girls in the two classes?
六1班和六2班的部分同学参加某次数学竞赛，六1班的男生平均成绩是71分，女生平均成绩是76分，全班同学的平均成绩是74分；六2班的男生平均成绩是81分，女生平均成绩是90分，全班同学的平均成绩是84分，又知两个班所有男生的平均成绩是79分，两个班所有女生的平均成绩是多少分？
<gadget id="calculator">7 / 2</gadget>
<output>7/2 = around 3.5</output>

<gadget id="calculator">294 / (7/2)</gadget>
<output>84</output>

<result>84</result>