SOLUTION: If 70% of the students in a school are boys and the number of girls is 540,find the number of boys in the school ?

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Question 1015254: If 70% of the students in a school are boys and the number of girls is 540,find the number of boys in the school ?
Found 2 solutions by Edwin McCravy, ptaylor:
Answer by Edwin McCravy(20059)   (Show Source): You can put this solution on YOUR website!
Girls in that school could have their pick for a bf! :)

S = B + G

If 70% of the students in a school are boys

.70S = B

and the number of girls is 540,

G = 540



1.  Substitute 540 for G in S=B+G.

S = B+540

2. Substitute (B+540) for S in 0.70S=B

0.70(B+540)=B
 
Distribute

0.70B+378=B
      378=B-0.70B
      378=1.00B-0.70B
      378=0.30B
 378/0.30=B 
     1260=B   

There are 1260 boys.

Edwin
Answer by ptaylor(2198)   (Show Source): You can put this solution on YOUR website!
Let x=total number of students
0.70x=number of boys
0.30x=number of girls=540
Sooooo:
0.30x=540
x=540/0.30=1800 ---total number of students
0.70*1800=1260=number of boys
or
1800-540=1260=number of boys
Hope this helps----ptaylor
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