Which of the following is closest in value to (9^9)-(9^2)?

Question

A. 9^9
B. 9^8
C. 9^7
D. 9^6
E. 9^5

Bunuel · Accepted Answer

Easier way:  9^9 - 9^2=9^2(9^7-1) . Now  9^7-1  is very close to  9^7 , hence  9^9 - 9^2=9^2(9^7-1)\approx{9^2*9^7=9^9} .

Answer: A.

pmenon · Answer

i would say A as well ... i just simplified out to 9^2*(9^7 - 1) ... and the 1 is pretty much negligible ... so we go back down to 9^9 ...

jallenmorris · Answer

I think the answer is going to be A. The reason is that subtracting 81 from 9^9 is not going to subtract enough to get it anywhere close to 9^8. 9^8 is going to be such a huge number that when you multiply it by 9 again to get 9^9, subtracting 81 (i.e., 9^2) from it, the result will still be must closer to 9^9 than any of the others.

puma

Which of the following is closest in value to (9^9)-(9^2)?

a) 9^9
b) 9^8
c) 9^7
d) 9^6
e) 9^5

shalva · Answer

We need to get approximate answer. I'm pretty sure exact number is unreachable w/o Excel spreadsheets.

bibha · Answer

Which of the following is closest to 9^9 - 9^2?

A. 9^9
B. 9^8
C. 9^7
D. 9^6
E. 9^5

gurpreetsingh · Answer

IMO A, whats the OA? clearly 9^8 <9^9 - 9^2 < 9^9 now 9^9 - 9^2 will be closer to 9^9 if 9^9 - 9^2? lies between \frac{(9^9+9^8)}{2} and 9^9 else 9^8 \frac{(9^9+9^8)}{2} = 9^8*\frac{(9+1)}{2} = 9^{8} * 5 9^9 - 9^2 = 9^8( 9 - 9^{-6}) > 9^8 * 8 > 9^8*5 since 9^9 - 9^2 is greater than \frac{(9^9+9^8)}{2} i.e 9^{8} * 5 This lies closer to 9^9

PareshGmat · Answer

Answer = A
9^9 is way too high compared to 9^2

Bunuel · Answer

9^9 is much larger number than 9^2 and as we need approximate value then it's pretty much negligible in this case, so: (9^9)-(9^2) = ~9^9. Answer: A. Similar questions to practice: the-value-of-10-8-10-2-10-7-10-3-is-closest-to-which-of-95082.html which-of-the-following-is-closest-to-10180-1030-a-110224.html which-of-the-following-best-approximates-the-value-of-q-if-99674.html new-tough-and-tricky-exponents-and-roots-questions-125956-40.html if-x-10-10-x-2-2x-7-3x-2-10x-2-is-closest-to-143897.html 1-0-0001-0-04-10-the-value-of-the-expression-above-is-59398.html m24-q-7-explanation-76513.html 10-180-10-30-which-of-the-following-best-approximates-84309.html if-x-2-b-8-8-8-6-for-which-of-the-following-b-values-160197.html if-x-3-000-then-the-value-of-x-2x-1-is-closest-to-166128.html Hope it helps.

PareshGmat · Answer

9^9  is way too high than  9^2

So answer = A = 9^9

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Which of the following is closest in value to (9^9)-(9^2)?

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Which of the following is closest in value to (9^9)-(9^2)?

Prep Toolkit

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