Răspuns:
7 vaci ______14 oi_______182kg
10 vaci______7 oi________156kg |×2
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7vaci_______14oi______182
20vaci_______14oi____312
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13 vaci = 130
1 vaca =130 :13 =10
7 oi =156-10×10
7 oi=56
1 oaie= 56:7
1oaie= 8 kg