Question

trei covrigi si 4 paini cantaresc 2300g iar 7 covrigi si 7 paini cantaresc 4200g.un covrig cantareste:a)40g,b)20g,c)100g,d)80.plise imi trebuie pentru azi!!!!pliseeee...

Answer 1

3C+4p=2300
7c+7p=4200
Împărțim a doua ecuație la 7
C+p=600
P=600-c
Înlocuim in prima ec
3C+4(600-c)=2300
3C+2400-4c=2300
C=2400-2300
C=100
Varianta corecta e c)100g

Answer 2

3 c................................ 4 p.........................2300 g |*7
7 c............................... 7 p..........................4200 g |*4
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21 c............................. 28 p..........................16100 g
28 c..............................28 p.........................16800 g
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7 c..................................../..............................700 g
1 c= 100 g

Raspuns: C) 100 g