The official question is:
The value of (10^8-10^2)/(10^7-10^3) is closest to which of the following?
A)1
B)10
C)10^2
D)10^3
E)10^4
Since the answer choices are so spread out, we can be quite aggressive with our estimation.
First, 10^8 - 10^2 can be rounded to 10^8
Is this reasonable? Well, 10^8 equals 100,000,000, so subtracting 10^2 (aka 100) from 100,000,000 still leaves us with about 100,000,000
Similarly, 10^7 - 10^3 can be rounded to 10^7 (10,000,000 - 1000 is pretty close to 10,000,000)
So, by estimating, we get:
(10^8 - 10^2)/(10^7 - 10^3) = (10^8)/(10^7) [approximately]
= 10^1 = B
Cheers,
Brent
Gmat Prep 1
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