posted by Surya on .
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?
initially, b/g = 1/4
after some left, (b-2)/(g-48) = 2/7 since there were groups of 2 boys and 7 girls.
7(b-2) = 2(4b-48)
b = 82
so g = 328
so, at first there were 410 children
after kids left, there were
making 40 groups of 2boys and 7girls
Thank you very much for your kind help.
Can understand clearly.
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