Răspuns :
regula de trei simple.
notam cu x = kg de grau
x=(25×4):3=100:3=33,(3) kg
notam cu x = kg de grau
x=(25×4):3=100:3=33,(3) kg
4 kg grau....................3 kg gris
x.................................25 kg gris
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x=4·25:3=33,33 kg grau
x.................................25 kg gris
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x=4·25:3=33,33 kg grau