# The ratio of boys to girls is 4:5,when 9 boys added the ratio became 1:1 how many girls where thereat first?

2
by yuan6

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

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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

2016-02-26T20:42:57+08:00
The answer is girl 4:5