Answers

2015-09-15T17:47:47+05:30
Let the ratio constant = x
the ratio of girls and boys = 3:7
∴no.of girls = 3x
∴no.of boys = 7x
total no. of girls and boys = 30
⇒3x + 7x = 30
⇒10x = 30
⇒  x = 30/10
⇒  x = 3
∴no. of boy = 7x ⇒7*3 ⇒21.
∴ no. of boys = 21
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