Răspuns :
In 3 ore, 5 pompe extrag 128 butoaie ulei
Atunci intr-o ora 5 pompe extrag 128/3 butoaie ulei
Intr-o ora, o pompa extrage 128/3 : 5 = 128/3 x1/5 = 128/15 butoaie ulei
Intr-o ora, 4 pompe extrag 128/15 x 4 = 512/15 butoaie ulei
In 4 ore, 4 pompe extrag 512/15 x 4 = 204815 bidoane ulei = (2040+8)/15 = 2040/15 + 8/15 = 136 bidoane si 8/15
Atunci intr-o ora 5 pompe extrag 128/3 butoaie ulei
Intr-o ora, o pompa extrage 128/3 : 5 = 128/3 x1/5 = 128/15 butoaie ulei
Intr-o ora, 4 pompe extrag 128/15 x 4 = 512/15 butoaie ulei
In 4 ore, 4 pompe extrag 512/15 x 4 = 204815 bidoane ulei = (2040+8)/15 = 2040/15 + 8/15 = 136 bidoane si 8/15