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?
+1005 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
I have a question, why do you use the 220 instead of 280 whihc you got in your calculations?
+1005 x = 280, and that's the number of seniors. However we are solving for number of non-seniors so 500-280 =220.
+1005 we multiply since 100-30 = 70% play musical instruments, and 220 is the TOTAL number of non-seniors.
