Question 962398
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If 5/7 are boys, 2/7 are girls so (2/7)(100%)=28.57% are girls.
So 300 is 28.57% of: 300/0.2857=1050
There are a total of 1050 students
And 5/7 are boys: 5/7(1050)=750 
ANSWER: There are 750 boys in the school.