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Kyra observed that 85% of the students at a library liked reading mystery stories. If 30 students at the library did not like reading mystery stories, the number of students at the library who liked mystery stories was _____. (only put numeric values, no other symbols)

User DMI
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2 Answers

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The first thing we must do is find the percentage of students who do not like to read mystery stories.
We have then:

100-85 = 15
Then, to find the number of students who like to read mystery stories, we can make the following rule of three:
15% ----------------> 30 students
85% ----------------> x
From here, we clear the value of x.
We have then:

x = (85/15) * (30) x = 170
Answer:
the number of students at the library who liked mystery stories was 170
User Ethan Li
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It is said that 85% of the students liked reading mystery stories. This means the remaining 15% don't like to read these stories. If there are 30 students belonging to the second category, then the number of students who liked reading mystery stories is (30/0.15)*0.85 equal to 170 students out of 200 students. 
User Tobias Dekker
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