Question

Pentru 5 rochii si doua costume sunt necesari 25 m stofa , iar pentru 7 rochii si 10 costume , 71 m stofa . Cati metri de stofa va cumpara mama daca doreste o rochie si un costum? Va rog urgent dau coroana

Answer 1

5 rochii ........................... 2 costume ......................... 25 m stofa | ×5

7 rochii ............................ 10 costume ........................ 71 m stofa

25 rochii ........................... 10 costume ............................ 125 m stofa

7 rochii .............................. 10 costume .............................. 71 m stofa

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18 rochii ............................... // ................................................... 54 m stofa

1 rochie = 54 : 18

1 rochie = 3 m stofa

5 × 3 m stofa ............................. 2 costume ............................. 25 m stofa

15 m stofa ................................... 2 costume .............................. 25 m stofa

2 costume = 25 - 15

2 costume = 10 m stofa

1 costum = 10 : 2

1 costum = 5 m stofa

3 m + 5 m = 8 m stofa ( pentru 1 rochie si un costum )