SOLUTION: On a school test, The average score for the girls in the class is 91, and the average score for the boys in the class is 85. If the average score for the class is 89, what fraction

Question 479364: On a school test, The average score for the girls in the class is 91, and the average score for the boys in the class is 85. If the average score for the class is 89, what fraction of the class are boys?
I should resolve it by a system...
91x + 85y= 89 (x+y)
But then??
Thanks in advance.
Answer by edjones(8007) (Show Source): You can put this solution on YOUR website!
(91x+85y)/(x+y)=89
91x + 85y= 89 (x+y)
...=89x+89y
2x=4y
y=x/2
1/3 of the class are boys.
.
Ed
RELATED QUESTIONS
In a class of 10 boys and 15 girls, the boys� average score on the final exam was 80 and... (answered by solver91311)

In a certain class there are 12 boys and 18 girls, if the average of class for an... (answered by veerajgrewal)

There are 3 times more boys than girls in a math class. The average score of the boys on (answered by greenestamps)

In a physics class the ratio of girls to boys is 1:3.The girls average score in a test... (answered by robertb)

In a class, the number of boys and girls are in ratio 3:2. In a test, the mean score for... (answered by ankor@dixie-net.com)

In a certain class, there are 14 boys and 21 girls. If the average score on an exam is 92 (answered by alicealc)

In a class test, the average score for the girls was 83 and the average score for the... (answered by ikleyn)

A class of 20 students took a math test. The 12 girls in the class had an average score... (answered by stanbon)

Average(arithmetic mean) of test scores in class R: average score for the boys: 90... (answered by stanbon)