Question 740765
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The original number of students was 600.  After 60 new students are admitted, the total number of students is 660.<br>
The resulting ratio of boys to girls is 13:9.<br>
Let 13x = new number of boys
Let 9x = new number of girls<br>
13x+9x = 660
22x = 660
x = 30<br>
The new number of boys is 13x = 390.<br>
The original number of boys was 360.<br>
The number of new boys admitted was 390-360 = 30.<br>
ANSWER: 30 new boys<br>