I want to know the answer to the following question:
How many people ride the metro system each day?
All the background I'm provided with is that "The metro is one of the busiest in the world transporting approximately 4.5 million people every day, surpassed only by subway lines in Moscow (7.5 million), Tokyo (5.9 million), and New York City (5.1 million).". Is that enough to answer the question?