ratio and proportion

Deepak BoraNewbie

# The ratio of boys to the number of girls in a school of 560 pupils is 5 : 3 . if 10 new boys are admitted , find how many new girls may be admitted so that the ratio of the number of boys to the number of girls may change to 3 : 2

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Total number of students = 560

And Ratio of boys to the number of girls = 5:3

âˆ´ Number of boys = 5/8 Ã— 560

= 350

Number of girls = 3/8 Ã— 560

= 210

After adding 10 new boys,total number of boys = 360

Let the number of girls added to make the new ratioÂ (boys : girls)3:2 is ‘x’

âˆ´ 360/210+x = 3:2

720 = 3(210+x)

720 = 630 +Â 3x

90 = 3x

âˆ´ x= 30

So we have to add 30 girls to make ratio 3:2