corbul mare-x
corbul mic-y
x-y=51
x/2 supra 2=y
x/2*1/2=y
x/4=y
x-x/4=51 aducem la acelasi numitor
4x-x=204
3x=204
x=68 y=68/4=17
x+10+20=1/10*1000
x+30=1000/10
x+30=100
x=100-30
x=70 de ani ar mai trai corbul mare
y=x/4
x/4+10+20=1/10*1000
x/4+30=100 aducem la acelasi numitor
x+120=400
x=400-120
x=280 de ani ar mai trai corbul mic