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# math

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a city poplation of 350,000 the poplation has decreased by 30% in the past ten years what was the poplation of the city ten years"

Jan 26, 2023

#1
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I'm guessing the question is asking for the population ten years ago.

Since the population has decreased by 30%, the population now (350,000) is 70% = 7/10 of the original population. So then,

$$(\text{population 10 years ago})\cdot\frac{7}{10}=350,000$$.

Multiplying both sides by 10/7 to cancel out the fraction gives

$$\text{population 10 years ago} = 350,000\cdot\frac{10}{7}=\boxed{500,000}$$

Jan 26, 2023