NEED HELP

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NEED HELP

by REINE » Sat Mar 18, 2017 2:48 am
999
----------
100 + 1
---------------
999

which of the following is closest to the value above

a; 10
b; 1
c; 0.1
d; 0.01
e; 0.001

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by GMATGuruNY » Sat Mar 18, 2017 3:10 am
REINE wrote:999/(100 + 1/999)

which of the following is closest to the value above

a; 10
b; 1
c; 0.1
d; 0.01
e; 0.001
The word in blue implies that we can BALLPARK.
Compared to 999 and 100, 1/999 is so small that it can be ignored in the calculation.
Thus:
999/(100 + 1/999) ≈ 999/100 ≈ 1000/100 = 10.

The correct answer is A.
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by Jay@ManhattanReview » Sat Mar 18, 2017 4:14 am
REINE wrote:999
----------
100 + 1
---------------
999

which of the following is closest to the value above

a; 10
b; 1
c; 0.1
d; 0.01
e; 0.001

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We have to get the approximate value of 999/(100 + 1/999).

999/(100 + 1/999) ≈ 1000/(100 + 1/1000); '999' is approximated to '1000.'

1000/(100 + 1/1000) = 1000/(100 + 0.001) = 1000/100.001 ≈ 1000/100 ≈ 10; '100.001' is approximated to '100.'

The correct answer: A

Hope this helps!

Relevant book: Manhattan Review GMAT Math Essentials Guide

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by [email protected] » Sat Mar 18, 2017 10:23 am
Hi REINE,

From the answer choices, you can see that each answer is 10 TIMES the answer that immediately follows it. As such, these answers are essentially about a 'decimal shift' and we almost certainly use estimation to get to the correct answer.

999 is really close to 1,000
100 + (1/999) is really close to 100

Thus, the approximate fraction 1000/100 is about 10

Final Answer: A

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by Brent@GMATPrepNow » Sun Mar 19, 2017 11:48 am
999/(100 + 1/999)

which of the following is closest to the value above

a) 10
b) 1
c) 0.1
d) 0.01
e) 0.001

999/(100 + 1/999) = 999/(100 + some very small value like 0.00something)
≈ 999/100.00something
≈ 999/100
≈ 1000/100
= 10
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