Answers

  • Brainly User
2016-02-24T12:00:54+08:00

This Is a Certified Answer

×
Certified answers contain reliable, trustworthy information vouched for by a hand-picked team of experts. Brainly has millions of high quality answers, all of them carefully moderated by our most trusted community members, but certified answers are the finest of the finest.
Ratio of boys to girls ⇒  4:5
Number of boys: 4x
Number of girls: 5x

If 9 boys are added, the ratio becomes 1:1, or boys = girls.
Number of boys: 4x + 9
Girls:  5x

Equation:
  
     boys = girls
     4x + 9 = 5x
     9 = 5x - 4x
     9 = x   or x = 9

Substitute 9 to to the numbers of boys and girls with ration 4:5:
    Number of boys: 4x   ⇒  4(9) = 36 boys
    Number of girls:  5x   ⇒  5(9) = 45 girls

ANSWER:  There were 45 girls at first.

Check:
   Boys to girls ratio ⇒  4:5
      36:45 = 4:5
  
   When 9 boys are added to boys, the ratio becomes 1:1.
       (36+9) : 45 = 1:1
              45 : 45 = 1: 1


0
2016-02-26T20:42:57+08:00