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The ratio of the number of junior high students to the number of senior high students in a school is 7 to 9. If there are 100 more senior high students than junior high students, how many junior high students are there?

 Jul 27, 2015

Best Answer 

 #1
avatar+129852 
+6

Let N be the number of junior high students. Then 100 + N = the number of senior high students.

 

And we are told that :

 

N / [100 + N ] = 7/ 9    cross multiply

 

9N = [100 + N] * 7   simplify

 

9N = 700 + 7N    subtract 7N  from both sides

 

2N = 700    divide both sides by 2

 

N = 350   and this is the number of junior high students....the number of senior high students is 450.....and their ratio is 350 / 450  = 7 /9

 

 

   

 Jul 27, 2015
 #1
avatar+129852 
+6
Best Answer

Let N be the number of junior high students. Then 100 + N = the number of senior high students.

 

And we are told that :

 

N / [100 + N ] = 7/ 9    cross multiply

 

9N = [100 + N] * 7   simplify

 

9N = 700 + 7N    subtract 7N  from both sides

 

2N = 700    divide both sides by 2

 

N = 350   and this is the number of junior high students....the number of senior high students is 450.....and their ratio is 350 / 450  = 7 /9

 

 

   

CPhill Jul 27, 2015
 #2
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0

@CPhill your answer is WRONG

 Jul 13, 2016
 #3
avatar+33661 
+5

The logic and evaluation is sound!  

 

If you think it is wrong you need to explain why.

Alan  Jul 13, 2016

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