Hi Vincen,

When dealing with exponents in questions such as these, it's important to understand the 'magnitude' of each power and the meaning of the differences in the values.

For example 10^3 and 10^2 might 'look' similar, but they're really not "close":
10^3 = 1,000
10^2 = 100
10^3 - 10^2 = 900... meaning that the difference of those two numbers is actually far closer to 10^3 than you might initially realize. The same idea applies to this prompt.

11(10^10) - 4(10^4)

11(10^10) is 110,000,000,000
4(10^4) is 40,000

The difference of those numbers is 109,999,960,000, which is relatively close to 10^11

Final Answer: E

GMAT assassins aren't born, they're made,
Rich

Vincen wrote: ↑

Sun Sep 10, 2017 12:20 pm

Which of the following is the closest to 11*10^10-4*10^4 ?

A. 10^2
B. 10^7
C. 10^8
D. 10^9
E. 10^11

OA is E.

What are the calculus to determine the correct answer?

Since 4*10^4 is relatively small when compared to 11*10^10, then the difference would still be close to 11*10^10, which is approximately 10*10^10 = 10^11.

Answer: E