13 v ................48 o ............ 226 litri
13 v ...............39 o ............. 208 litri
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/....................9 o ................. 18 litri
1) 18 : 9 = 2 litri ( o oaie )
2) 2 x 48 = 96 litri (48 oi )
3)226-96 = 130 ( 13 v )
4) 130: 13 = 10 litri ( o vaca)