Oh, actually you are right. It does say LEAST, so the answer is clearly (C). Hmm…I’m still not sure if the GRE would include this. Maybe, but I wouldn’t worry about it. BTW what was the original source?

]]>Your method is right, but it requires approximation… you wont get a correct answer.

Though the answer is 65 as the upper limit of n would be less than 75 and lower limits greater than 45…

Great to know these aren’t pertinent to gre.

Thanks a ton…. i’ll go through the propounded article…..

http://magoosh.com/gre/2012/gre-exponents-practice-question-set/

They are indeed tricky – meaning check your answer to make sure you didn’t fall for any traps.

For your question above:

10^15 = 2^15 x 5^15. Then things become kind of nasty, without a calculator. But I think of it this way: 5^3 = (apprx) 2^7, thus 5^15 = (apprx) 2^35. Thus 2^35 x 2^15 = 10^15, so n is apprx 50, which is not an answer choice.

My guess is this question is faulty. (A) there is no correct answer (B) you may see this on the GMAT but it is beyond the scope of the GRE.

The questions in the link above are a more accurate indication of what you will see test day :).

Hope that helps

]]>I have a doubt in inequalities….

Q)Which of the following option should be the least value of n that satisfy the inequality,

2^n>(10)^15?

a)30

b)45

c)60

d)75

e)90

I wanted to know methods to solve one like of this…?

Please help me out.