Răspuns :
7 costume ............21 m
250 '' ...............x
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x =250*21/7 =750 m
250 '' ...............x
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x =250*21/7 =750 m
21:7=3 m stofa un costum
250×3=750 m de stofa pt. 250 costume
250×3=750 m de stofa pt. 250 costume