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

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Intern
Joined: 11 Nov 2014
Posts: 12
GMAT Date: 01-15-2015
GPA: 3.4
According to the graph above, if 80 percent who were under 18 years ol  [#permalink]

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Updated on: 13 May 2015, 03:03
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Difficulty:

15% (low)

Question Stats:

81% (02:02) correct 19% (01:46) wrong based on 244 sessions

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Screen Shot 2015-05-12 at 5.09.09 PM.png [ 97.59 KiB | Viewed 6875 times ]
According to the graph above, if 80 percent who were under 18 years old and living in the United States in 1970 are still living in the Unites States in 2020, the number of the people will be approximately what fraction of the number of people 50 years old or older living in the United States in 2020?

A. 7/8
B. 7/9
C. 7/10
D. 7/12
E. 7/15

Originally posted by mb9252 on 12 May 2015, 08:51.
Last edited by Bunuel on 13 May 2015, 03:03, edited 1 time in total.
Renamed the topic and edited the question.
Manager
Joined: 12 Nov 2014
Posts: 63
Re: According to the graph above, if 80 percent who were under 18 years ol  [#permalink]

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12 May 2015, 09:47
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3
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

Hope you understood.

Consider giving Kudos if explanation is clear!

Ambarish
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Kindly press Kudos if the explanation is clear.
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##### General Discussion
e-GMAT Representative
Joined: 04 Jan 2015
Posts: 2069
Re: According to the graph above, if 80 percent who were under 18 years ol  [#permalink]

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12 May 2015, 10:13
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 $$\frac{56}{120} = \frac{7}{15}$$

Hope it helps

Regards
Harsh
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Intern
Joined: 11 Nov 2014
Posts: 12
GMAT Date: 01-15-2015
GPA: 3.4
Re: According to the graph above, if 80 percent who were under 18 years ol  [#permalink]

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12 May 2015, 10:40
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.
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Re: According to the graph above, if 80 percent who were under 18 years ol  [#permalink]

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09 Feb 2018, 10:15
Hello from the GMAT Club BumpBot!

Thanks to another GMAT Club member, I have just discovered this valuable topic, yet it had no discussion for over a year. I am now bumping it up - doing my job. I think you may find it valuable (esp those replies with Kudos).

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Re: According to the graph above, if 80 percent who were under 18 years ol &nbs [#permalink] 09 Feb 2018, 10:15
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