Maths

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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 -

    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 -

    Dear Steve,

    Thank you very much for your kind help.
    Can understand clearly.

    With regards,
    Surya

  • Maths -

    Martha spent 4/a of her allowance on food and shopping.what fraction of her allowance had she
    left

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