Every 100 tons of the earth's crust contain about 28 tons of silicon. What is the ratio of the weight of silicon to the weight of crust? of the weight if crust to the weight of silicon?

Answer: 28/100 = 7/25 100/28 = 25/7 Explanation:

The wording "the ratio of A to B" means A/B.

Here, "the ratio of the weight of silicon to the weight of crust" means ...

... (28 tons) / (100 tons)

Canceling common factors (and common units), this is ...

... 28/100 = 7/25

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Then "the ratio of the weight of crust to the weight of silicon" means ...

... (100 tons) / (28 tons) = 100/28 = 25/7