Răspuns :

peste=cap+trunchi+coada
coada=1.5

cap=coada+trunchi/2
cap=1.5+trunchi/2

trunchi=cap+coada
trunchi=1.5+trunchi/2+1.5
trunchi=3+trunchi/2
2trunchi=6+trunchi
2trunchi-trunchi=6
trunchi=6 kg

cap=1.5+trunchi/2
cap=1.5+6/2
cap=1.5+3
cap=4.5 kg

peste=4.5+6+1.5
peste=12 kg