A chicken egg is about $5$ cm in length, and an ostrich egg is about $15$ cm in length. If the chicken egg is similar to the ostrich egg (in other words, they have proportional dimensions), and if two chicken eggs is considered a "normal serving", then about how many "normal servings" would one ostrich egg provide? (Note- the "formulas" for similar solids: similar solids in which the ratio of linear measures is $ a:b $ have an area ratio of $ { a }^{ 2 }:{ b }^{ 2 } $ and a volume ratio of $ { a }^{ 3 }:{ b }^{ 3 } $). (No Calculator)