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in a school of 5/7 of the students are boys . if there 300 girls find the number of boys ?

 May 23, 2014

Best Answer 

 #2
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yeah totally thanks 

 May 23, 2014
 #1
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If 5/7 are boys, than 2/7 must be girls.

Let x be the total number of students.

Then 2/7 of x = 300     or, in math terms

(2/7)x = 300        Multiply both sides by the reciprocal of (2/7) ⇒ (7/2)

x = 300(7/2) = 1050 = total students

Then.... the total students - the number of girls = the number of boys

So 1050 - 300 = 750      And that's the number of boys.

 

Note something else......if 2 parts of the 7 are girls = 300, then there must be 150 students in each "part"  

Then, since the boys are 5 "parts", then 5(150) = 750 !!!

Does that make sense??

 May 23, 2014
 #2
avatar+11912 
+10
Best Answer

yeah totally thanks 

rosala May 23, 2014

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