Carbon dioxide comprises, on average, about 397 parts per million of

Question

Carbon dioxide comprises, on average, about 397 parts per million of the Earth's atmosphere, on a molecular basis. In an even sample of the Earth's atmosphere consisting of 4 billion molecules, approximately how many of those molecules would be expected to be carbon dioxide? (1 billion = 1,000,000,000)

A. 160,000
B. 1,000,000
C. 1,600,000
D. 10,000,000
E. 16,000,000

A. 160,000
B. 1,000,000
C. 1,600,000
D. 10,000,000
E. 16,000,000

Bunuel · Answer

Similar question to practice: https://gmatclub.com/forum/the-concentr ... 23165.html

amarsinha · Answer

In 1000000 molecules of atmospher, 397 part is carbon dioxide. 
So, in 4 billion molecules, carbon dioxide = (397/10^6)4*10^9 ~ 1600*10^3 = 1600000

lacktutor · Answer

397 -->  10^{6} 
 x -->  4*10^{9}

x =  \frac{397*(4*10^{9})}{10^{6}}  ≈  \frac{400*4*10^{9}}{10^{6}} = 1600*10^{3} =1 600 000

The answer is C

Kinshook · Answer

Given: 
1. Carbon dioxide comprises, on average, about 397 parts per million of the Earth's atmosphere, on a molecular basis.
2. In an even sample of the Earth's atmosphere consisting of 4 billion (4000 millions) molecules
3. 1 billion = 1,000,000,000

Asked: Approximately how many of those molecules would be expected to be carbon dioxide?

1. Carbon dioxide comprises, on average, about 397 parts per million of the Earth's atmosphere, on a molecular basis.
2. In an even sample of the Earth's atmosphere consisting of 4 billion (4000 millions) molecules

Approximately number of those molecules expected to be carbon dioxide = 397 parts/million * 4000 millions = 397*4000 = 1,588,000 = 1,600,000 approx

IMO C

ScottTargetTestPrep · Answer

We can create a proportion (using 1 for 1 million and 4,000 for 4 billion since 4,000 million is 4 billion):

397/1 = x/4,000

x = 397 * 4,000 ≈ 400 * 4,000 = 1,600,000

Answer: C

Carbon dioxide comprises, on average, about 397 parts per million of

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Carbon dioxide comprises, on average, about 397 parts per million of

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