1) 1h=60 min
900m .......3min
Xm...........60min
X=900x60/3=18000m
2)V=l la a3a=0.4X0.4X0.4=0.064 m*3=64l
3) ....fizica
4)x+y=20 =>X=20-Y
5x-2y=72 =>5(20-y)-2y=72=>y=4
x=20-4=16
5)....fizica
6) x-nr de ani trecuti
6+x-varsta Andrei viitor
15+x-varsta Maria viitor
=> 2(6+x)=15+x=> x=3ani