The mass of the heaviest flying bird, the bustard, which lives in Africa, is on average 18 kg. The heaviest flightless

The mass of the heaviest flying bird, the bustard, which lives in Africa, is on average 18 kg. The heaviest flightless is the ostrich: 25% of the bustard mass is only 3% of the average ostrich mass. Calculate from these data the mass of the ostrich.

Let’s calculate what 25% of the bustard’s mass is equal to if it weighs 18 kilograms.
18 × 25: 100 = 4.5 kilograms.
According to the condition of the problem, 4, 5 kilograms is 3% of the average weight of an ostrich. That is, the mass of the ostrich will be:
4.5 × 100: 3 = 150 kilograms.
Answer: the average weight of an ostrich is 150 kilograms.