then 12 boys fill 12 notebooks in 6 weeks,

and 12 boys fill 24 notebooks in 12 weeks;

If 4 girls fill 4 notebooks in 4 weeks,

then 12 girls fill 12 notebooks in 4 weeks,

and 12 girls fill 36 notebooks in 12 weeks;

Hence 12 girls and 12 boys fill 24+36=60 notebooks in 12 weeks.

Source: Longley-Cook, L. H.

Categories: Reasoning, Arithmetic, Rates, Poetic

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