x=crina
y=valentina
z=adrian
x+y+z=200
x/2=y/3=z/5=k nr necunoscut
x/2=k =>x=2k
y/3=k =>y=3k
z/5=k =>z=5k
2k+3k+5k=200
10k=200
k=200/10
k=20
x=2k=>x=2x20 =>x=40 nr de probleme rezolvate de Crina
y=3k=>y=3x20=>y=60 ----------I I-----------------------deValentina
z=5k=>z=5x20=>z=100----------I I------------------------de Adrian