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2014-05-17T13:15:55+03:00
/ =supra
x = drum
l zi =x/5 km
ll-a zi =3/4(x-x/5) km
lll-a zi =15 km
x/5+3/4(x-x/4)+ 15=x
x/5+3/4x-3x/20x+15=x     dai numitor comun 20
4x+15x-3x+300=20x
19x-3x-20x=-300
-4x=-300 .(-1)
x=300/4
x =75 km 
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