Posted by **Surya** on Wednesday, March 7, 2012 at 9:14am.

A moment ago, 80% of the children in a hall were girls. 48 girls and 2 boys left the hall. The remaining children were then told to form groups of 9. In each group, there were 2 boys. How many children were there in the hall first?

- Maths -
**Steve**, Wednesday, March 7, 2012 at 12:39pm
initially, b/g = 1/4

after some left, (b-2)/(g-48) = 2/7 since there were groups of 2 boys and 7 girls.

g=4b

7(b-2) = 2(4b-48)

b = 82

so g = 328

so, at first there were 410 children

after kids left, there were

80 boys

280 girls

making 40 groups of 2boys and 7girls

- Maths -
**Surya**, Thursday, March 8, 2012 at 9:33am
Dear Steve,

Thank you very much for your kind help.

Can understand clearly.

With regards,

Surya

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