ca=c/3
2s+3c+12*c/3=152
s+4c+15*c/3=175
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2s+7c=152
s +9c = 175 I *2 si le scad
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18c-7c = 350-152
11c=198
c=198/11 = 18 lei o carte
ca= 18/3 = 6 lei un caiet
s=175-9*18 = 175 -162 = 13 lei un stilou
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Andrei: 1s+1c+1ca = 13+18+6 = 37 lei