A standard Blue Bird bus weighs around 10-15 tons (10,000 - 15,000 kg), depending on the model and configuration. Let’s assume an average weight of 12.5 tons (12,500 kg) for this calculation.

Now, let’s divide the total weight by the weight of a single bus:

273 billion metric tons ÷ 12,500 kg/bus ≈ 21,800,000 buses

So, approximately 21.8 million Blue Bird school buses would weigh around 273 billion metric tons.

Keep in mind that this is another purely theoretical calculation for entertainment purposes only.