SOLUTION: At an after school event, 5/9 of the students were 8th graders and the rest were 7th graders. Of the students who were in 7th grade, the ratio of boys to girls is 3:5. What percent
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-> SOLUTION: At an after school event, 5/9 of the students were 8th graders and the rest were 7th graders. Of the students who were in 7th grade, the ratio of boys to girls is 3:5. What percent
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Question 1108740: At an after school event, 5/9 of the students were 8th graders and the rest were 7th graders. Of the students who were in 7th grade, the ratio of boys to girls is 3:5. What percent of ALL students at the after school event were boys who are in the 7th grade? Answer by ikleyn(52803) (Show Source):
Let x = the number of the boys who were in 7th grade.
Let Z = the number of ALL students.
They want you determine the ratio x/Z (it is almost the same as percentage).
Let Y be the number of all 7th grade students.
Notice that = , as it follows from the condition.
Also from the condition = = .
Now we have EVERYTHING to calculate
= = = = .
Thus we just found the ratio = .
Hence, the percentage under the question is = = 16.667 % (approximately).
