SOLUTION: 5/7 of a group of students are girls .if the no.of girls is 18 more than the no.of boys .how many students are there altogether

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Question 1084644: 5/7 of a group of students are girls .if the no.of girls is 18 more than the no.of boys .how many students are there altogether
Answer by Edwin McCravy(20060) About Me  (Show Source):
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5/7 of a group of students are girls .if the no.of girls is 18 more than the no.of boys .how many students are there altogether
Let the number of students = n

5/7 of a group of students are girls .
That means that 5 sevenths are are girls and
the remaining 2 sevenths are boys 

So the number of girls = 5/7ths of n, or expr%285%2F7%29n 

And the number of boys = 2/7ths of n, or expr%282%2F7%29n

the no.of girls is 18 more than the no.of boys .
expr%285%2F7%29n %22%22=%22%22 expr%282%2F7%29n%22%22%2B%22%2218

Multiply every term by 7

5n %22%22=%22%22 2n%22%22%2B%22%22126

3n %22%22=%22%22 126

n %22%22=%22%22 42

Edwin