SOLUTION: There are 1200 pupils in a secondary school. The ratio if girls to boys is 5:7. How many boys and girls are there in the school?

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Question 428643: There are 1200 pupils in a secondary school. The ratio if girls to boys is 5:7. How many boys and girls are there in the school?
Answer by ewatrrr(24785) About Me  (Show Source):
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Hi

1200 pupils in a secondary school

Let x and (1200-x)represent the number of girls and boys respectively

Question Set Up the Proportion***



+5%2F7+=+x%2F%281200-x%29   | Cross Multiplying 

 7x = 5(1200-x)

 12x = 6000

  x =  500, the number of girls. the number of boys is 700  (1200-500)



CHECKING our Answer***

  5/7 = 500/700