The "() extension () contraction" in this question can't be done

Stretch and shrink

The unforgettable primary school life in the sixth grade composition

Yesterday, I was a freshman, today, I want to say this with tears: "goodbye, alma mater!" alma mater, you let me from a naughty boy who don't know anything, into a young pioneer who has ideals and ambitions, you lead me into the no

In the Spring Festival of a certain year, 2 billion firecrackers were set off in three days, and 0.05T sulfur dioxide was released. How many tons of sulfur-containing 1% coal is the sulfur dioxide released by 2 billion firecrackers

The mass fraction of SO2 is 50%;
Therefore, the sulfur content of 0.05T SO2 is 0.05 * 50% = 0.025t
It is equivalent to burning coal 0.025/1% = 2.5t

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