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help pls idk what to do

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In a high school with 500 students, 40% of the seniors play a musical instrument, while 30% of the non-seniors do not play a musical instrument. In all, 46.8% of the students do not play a musical instrument. How many non-seniors play a musical instrument?

May 5, 2020

#1
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Let's say the number of seniors is x.

3/5 x +(3/10 *(500-x)) = 468/1000 * 500

3/5 x+150 - 3/10 x = 234

3/10 x = 84

x = 84 * 10/3 = 280

500- x = 220 non seniors

220 * 7/10 = 154

If you don't understand anythign feel free to ask

May 5, 2020
#2
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I have a question, why do you use the 220 instead of 280 whihc you got in your calculations?

May 5, 2020
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x  = 280, and that's the number of seniors. However we are solving for number of non-seniors so 500-280 =220.

hugomimihu  May 5, 2020
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oh ok

also why do you multiply by 7/10?

Guest May 5, 2020
#5
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we multiply since 100-30  = 70% play musical instruments, and 220 is the TOTAL number of non-seniors.

hugomimihu  May 5, 2020