According to the graph above, if 80 percent who were under 18 years ol

Number of people who were under 18 years old and living in US in 1970 = 70 million
80 % of these people will be 0.80 * 70 million = 56 million

Number of people living in US who are 50 years or older in 2020 = 120 million.

Now the question is 56 million is what fraction of 120 million ?

i.e. 56/120 = 7/15

Answer E

Hope you understood.

Consider giving Kudos if explanation is clear!

Ambarish

Hi mb9252,

The question asks us to find the ratio of people who were under 18 years in 1970 and are still living in the country to the total number of people in 50 or older category in year 2020.

The key here is to note that people who were under 18 years in 1970 would be 50 years or older in 2020 ( as 2020 - 1970 = 50 years). The question tells us that 80% of people who were under 18 years in 1970 were still living in the country i.e. such people will be represented in 50 or older bar in the graph for the year 2020.

We can see from the graph that total number of people who were 50 or older in 2020 = 120 million.

Now we just need to find the number of people who were under 18 in 1970 and are still living in the country

So, we first need to find the number of people who were under 18 years in 1970 = 70 million

80% of such people are still living in the country in 2020 = 80% of 70 million = 56 million people.

We need to find the fraction of such people to the total number of 50 or older people in the country in the year 2020.

So, the desired fraction would be \(\frac{56}{120} = \frac{7}{15}\)

Thus answer is Option E

Hope it helps

Regards
Harsh
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this was the last question i saw on the gmat prep test and i had only 20 seconds to go so just picked a random answer out of the lot. After reading the explanation it looks really easy.

The image has the correct answer option marked on it. Can it be fixed?
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Number of people who were under 18 years old and living in the United States in 1970 = 70 million

70*80/100=56 million

The number of people 50 years old or older living in the United States in 2020=120 million

56/120=7/15

E
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I used the Empower method to narrow down the answer choices. After I figured out the answer was 56/120 , I realized this is slightly less than half (can also be written as 5.6/12) Half would be 6/12. All of the answer choices except E are very obviously larger than half. E is the only one that "fits"

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